I 



Dairy Arithmetic 



,• 



/ 



Fundamental Dairying 



and 



Dairy Arithmetic 



by 



Oscar Erf 



Professor of Dairying and Animal Industry 
Kansas State Agricultural College 



Manhattan, Kan., 

Printing Department, K.S. A.C. 

1906. 



\ 



E<i7 



By transfer 
14 Fi30? 



FUNDAMENTAL DAIRYING AND DAIRY ARITHMETIC. 



DIVISION ONE. 

MILK. 

1. Question. What is milk? 

Answer. Milk is the special fluid secreted by the females of 
milk giving animals (the Class Mammalia) for the purpose of 
nourishing the young until they are capable of seeking for them- 
selves the kind of food which they can easily digest. 

2. Q. Of what is milk composed? 
A. Of water and milk solids. 

3. Q. Is water in milk any different from distilled water? 
A. No. 

4. Q. What are the milk solids? 

A. The milk solids are fat, milk sugar, albuminoids, and ash. 

5. Q. What is milk serum? 

A. Milk serum is the water and all of the solids except the fat. 

6. Q. What are the fats in milk? 

A. The fats in milk are known as butter fats, and are so called 
because they are the chief constituents of butter. Fats are com- 
posed of fatty acids in combination with glycerine. Butter fats 
are a mixture of several distinct fats which have mainly as their 
fatty acids, stearic, palmitic, and oleic acids, in combination with 
glycerine. In connection with these there are a number of 
other fats that, when broken into their simple constituents, are 
volatile. The butter fats are the most variable constituents 
in milk. 

7. Q. What is the chief function of butter fat when taken into the body? 
A. It is to produce heat and fat. 

8. Q. How do butter fats exist in milk? 

A. In the milk serum in the form of very minute globules. 
This is called an emulsion. These globules vary in size, under 
normal conditions, from toooo of an inch to 20000 of an inch in di- 
ameter. It is estimated that in average milk there are 150,000 
globules in a single drop. 

9. Q. What is milk sugar? 

A. In general appearance, milk sugar resembles confectioner's 
sugar, although it is not so sweet. When taken into the body, its 
function, like that of fats, is to produce heat and fat. At high 
temperature, or on boiling, milk sugar caramelizes and is the prin- 
cipal cause of the peculiar scalded taste of boiled milk. In com- 
merce, milk sugar is used principally in lactated foods and in 
medicines. 



4 FUNDAMENTAL DAIRYING 

10. Q. What are the albuminoids? 

A. The albuminoids, commonly known as proteids, sometimes 
spoken of as protein, contain the nitrogen of milk. Their func- 
tion, when taken into the body, is to furnish food to blood, muscle, 
tendon, hair, nails, etc. In milk they exist in two forms, namely, 
the casein and albumen. 

11. Q. What is casein? 

A. Casein of milk is what is commonly known as curd. Curd 
is also proteid. It is that part which curdles or clabbers when 
milk sours. Casein exists in a semi-solid state in milk and is the 
constituent which gives to cheese its peculiar character. 

12. Q. What is albumen? 

A. Albumen is a clear, viscous substance of milk which re- 
sembles the white of egg:, and coagulates by heat. It is coagulated 
by heat but not by rennet; while casein is coagulated by rennet 
but not ordinarily by heat. The scum which forms on boiled milk 
is albumen. 

13. Q. What is ash? 

A. The mineral constituents of milk are termed, collectively, 
the ash. When the ash is separated from the rest of the milk, it 
resembles ordinary wood ash. The ash is composed chiefly of the 
phosphates of calcium (lime), potassium, iron and magnesium, and 
the chloride of potassium and chlorides of sodium (common salt). 
The principal function of ash, when taken into the body, is to fur- 
nish food for bone and nerves. Most of the ash is in solution in 
the milk. 

14. Q. What are the average per cents of the different constituents in 
milk? 



A. Milk. < { Fat, 3.60 fo [ Casein, 

/ Total solids, - ( Albuminoids, 3.40 % \ 3.00% 

12.50 % ( Solids not fat, \ Sugar. 4.79 % ( Albumen* 



( Water, 87.50 % 

•' ( 

Total solids, \ I Albuminoids, 3.40 % \ 3.00 % 

solids not fat, •< Sugar, 4.79 % { Albume 

8.90 % ( Ash, .71 % .40 % 

15. Q. How can you find the number of pounds of each constituent, if the 
weight of milk and the per cent of each constituent is given? 

A. Multiply the weight of milk by the per cent of constituent 
and divide by one hundred. 

Example. — Give the total number of pounds of each of the con- 
stituents in 200 pounds of milk containing the following per cents : 

Per f ent of 
constituent No. 

divided lb-;. 

by 100. Milk 

Water 8750 X 200 = 175.00 pounds of water. 

Total Solids 1250 X 200 = 25.00 pounds of total solids. 

Fat 0360 X 200= 7.20 pounds of fat. 

Albumen 0340 X 200 = 6.80 pounds of albuminoids. 

Milk Sugar 0479 X 200 = 9.58 pounds of milk sugar. 

Ash 0071 X 200 = 1.42 pounds of ash. 

16. Q. Does the per cent of constituents vary in milk? 
A. Yes. 

17. Q. May it vary in the milk given from day to day by the same cow? 



AND DAIRY ARITHMETIC. 



5 



A. Yes, it may also vary morning and evening of the same day. 

18. Q. Does the average per cent of these constituents vary greatly in 
the milk of a herd from day to day? 

A. No. The composition is quite constant in the mixed milk of 
a herd. 

19. Q. Why? 

A. Because a large number of cows giving milk of varying per 
cents of solids tend to equalize the solids in the mixed milk. 
Hence, from day to day the difference of the per cent of constitu- 
ents in milk from a herd is small compared with that of an indi- 
vidual cow. 

20. Q. What are the maximum and minimum per cents of constituents in 
milk? 

Maximum. Min'mum. 

Water " 90.fi9 80.32 

Fat 6.47 1.67 

Casein 4.23 1.79 

Albumen 4.44 .25 

Sugar 6.03 2.11 

Ash 1.21 .35 

N-ite.— This is according to Kcenig's analysis, collected from diffen-nt parts of the world, 
and represents a fair maximum and minimum ratio. It is a fact, however, that in one case 
of known record, a cow has given 11 per cent of butter fat. In a few cases cows have been 
known to yield 10 tier cent of butter fat in milk 

21. Q. Do the per cents of constituents of different breeds vary? 

A. Yes, to a certain extent; but it depends upon individual 
breeding. The following table gives results found at the New 
York Experiment Station for one year: 



Breed. 


Tot^l 
solids. 


Fats 


Casein. 


Sugar. 


Ash. 




11.80 
12.75 
15.40 
1-1 30 
14 90 
14.50 


3.46 
3.57 
5.61 


3.39 
4.43 
3.91 


4.81 
4.33 
5.15 


.74 
.70 






Devon 


5 12 
4 15 


3.61 
3.76 


5.11 

5.07 


.75 
.76 



22. Q. Do all cows of the same breed give the same per cent of constitu- 
ents ? 

A. No. There is much variation in the per cent of constituents 
in milk from different cows of the same breed. The above table 
represents the average composition of milk of the different 
breeds. 

23. Q. To what extent do the solids of milk vary in the different months 
of the period of lactation? 

The following instance of the variation in the milk of an indi- 
vidual cow is probably a fair illustration: 

First month 14.00 per cent. 

Second month 13. 5< .per cent. 

Third month 13.47 per cent. 

Fourth month 13.4H per cent. 

Fifth month 13 75 per cent. 

Sixth month 14 00 per cent. 

Seventh month 14. 18 per cent. 

Eighth month 14.33 per cent. 

Ninth month 14.83 per cent. 



G 



FUNDAMENTAL DAIRYING 



From the above table it is seen that in the second, third, fourth and fifth 
months in the period of lactation of the average cow. the per cent of solids 
is less than in the first, sixth, seventh, eighth and ninth months, but as a 
rule the greatest number of pounds of solids is found in milk given during 
the second, third, fourth and fifth months, due to the larger quantity given; 
so the total number of pounds of solids averages about the same.* 

24. Q. To what extent does the average monthly composition of milk 
vary? 

A. The average monthly composition is somewhat variable, 
though not as much as one per cent, as the following table shows: 



Srgar 

and ash. 



May 

June 

July 

August .... 
September. 
October 



Water. 


Solids. 


Fat. 


Solids 
not fat. 


Albu- 
mens. 


87 JO 


12 60 


3.63 


8.97 


3.14 


87 53 


1:2.47 


3.55 


8.92 


3 07 


87 63 


12 37 


3 59 


8 78 


3.00 


87.51 


12 49 


3 7S 


8 71 


3.05 


87 33 


12 67 


3.75 


8.92 


3.10 


86 87 


12 13 


4 00 


9 13 


3 36 



5 83 
5.85 

5.78 
5. T6 
5.82 
5 77 



25. Q. Does the per cent of constituents vary in the first and in the last 
milk of the same milking? 

A. The solids not fat remain quite constant, but the butter fats 
vary decidedly. An experiment with two cows at the Minnesota 
Experiment Station brings out this point clearly, as the following 
tables show: 

COW No. 1. 
First pint of milk. Last pint of milk. 

Total solids 9.42 19.49 

Fats 71 10.84 

Solids not fat 8.71 8.65 

Ash fi8 .72 

Casein, albumen 3.44 3.51 

COW No. 2. 

Total solids 10.10 18.47 

Fats 1.02 9.49 

Solids not fat 9.08 8.98 

Ash 70 .74 

Casein, albumen 3.35 3.65 



DIVISION TWO. 

BUTTER FAT. 

26. Q. What is the most valuable constituent of milk, from a commercial 
standpoint? 

A. Butter fat. 

27. Q. What is the range in percentage of butter fat in milk, cream and 
butter? 

A. The range is as follows: 

In milk, from 3 per cent to 10 per cent, average 3.8 per cent. 
In cream, from 10 per cent to 80 per cent, average 20.0 per cent. 
In butter, from 80 per cent to 92 per cent, average 85.0 per cent. 

Tne minimum per cent of butter fat in milk and butter is fixed by law in 
some .states. 



*Generall\ the greatest number of pounds of butter fat are produced the second month 
and the greatest number pouuds of milk in the third month of the period of lactation. 



AND DAIRY ARITHMETIC. < 

28. Q. What are the constituents, in connection with butter fat, that go 
to make up butter? 

A. (1) Water, (2) salt, (3) casein, (4) small amount of ash. (5) 
small amount of sugar. These constituents make what is known 
to be the "overrun" in butter. The "overrun" is the difference 
in weight of butter made, over the butter fat in milk. 

29. Q. What is the average per cent of "overrun" in butter? 
A. From 12 to 18 per cent. 

30. Q. What should be the par cent of water in butter? 
A. The established la vful limit is 16 per cent. 

31. Q. What should be the average per cent of salt in butter? 
A. From 2^ to 3 per cent. 

32. Q. Can the amount of butter be calculated if the weight of butter fat 
is known? 

Only approximately. It may be calculated by adding 14 per 
cent or 15 per cent or 16 per cent to the butter fat, or, the method 
which is more commonly followed, by adding i, £or \ to the butter 
fat. This variation depends upon the amount of fat lost, and the 
amount of water, salt and casein incorporated into the butter dur- 
ing the process cf manufacture. 

EXAMPLE. 

33. Q. How many pounds of butter can be made from 475 pounds of milk 
containing 3.8 per cent butter fat? 

A. 475 X .038 = 18 (pounds butter fat). 
iof 18 or 18 h- 6 = 3; then 

18 -j- 3 = 21, the number pounds butter that can be 
made from 475 pounds of milk. 

DIVISION THREE. 

CREAM. 

34. Q. What is cream? 

A. Cream consists of all portions of milk after a part of the 
milk serum has been removed. It contains not less than 10 per 
cent nor more than 80 per cent butter fat. Ordinarily, cream is 
that portion 4 of milk which rises to the top in a layer, upon letting 
milk set for a time, or is separated from it by centrifugal force. 

35. Q. Why does cream rise on milk? 

A. Cream contains more butter fat than milk, and since butter 
fat is the lightest constituent of milk, it rises for the same reason 
that wood floats on water. 

36. Q. How is cream separated from milk? 
A. Bv T different systems : 

(1) The Shallow Pirn System. — Milk is set in shallow pans for 24 
to H6 hours, during: which time the cream rises to the top. 

(2) The Dee}> Setting System. — Milk is set in deep, narrow cans, 
8 to 10 inches in width and 18 to 24 inches in depth. The cans are 
set in cold or ice water. The difference in temperature between 
the warm milk and the cold water in which it sets causes cream to 



O FUNDAMENTAL DAIRY fNG 

rise rapidly in the milk, due to the fact that the extreme differ- 
ence in temperature causes a vertical circulation at such a 
rapidity that the lighter parts of the milk are carried to the top 
wilh the current and are prevented from being carried down on 
account of their lightness. 

(3) The Centrifugal System. — Cream is separated by centrifugal 
force. The milk flows into a bowl, rotating very rapidly, causing 
the heavier constituents, such as milk sugar, casein, albumen and 
ash, to fly to the outside, while the lighter butter fat flows toward 
the center of the bowl, carrying with it some of the other con- 
stituents. 

37. Q. What is the composition of cream? 

A. Cream (containing 10 per cent to 30 per cent butter fat) has 
about the same per cent of milk sugar, albuminoids, and ash as 
milk. The fat varies decidedly and replaces the water in the 
cream. The per cent of fat in cream may range from 10 per cent 
to 80 per cent, according to the manner of skimming. An aver- 
age cream contains 22 per cent butter fat, 69 per cent water. 3.8 
per cent albuminoids, 4.6 per cent sugar, .6 per cent ash. 



DIVISION FOUR. 

OTHER MILK PRODUCTS. 

38. Q. What is skim-milk? 

A. Skim- milk is that portion of milk remaining after cream is 
extracted; or, in other words, it is the milk serum, though it may 
contain a small per cent of fat. The amount of fat remaining de- 
pends upon how thoroughly the milk has been separated. 

39. Q. Of what is skim-milk composed? 

A. Skim- milk has about the same per cent of solids not fat as 
whole milk, except about 2 per cent to 2^ per cent more water, 
and a small amountof butter fat (about .1 to .3 of one per cent) 
which cannot be practically separated from the milk. 

40. Q. What is skim-milk used for? 

A. In foreign countries it is largely used for human food, but 
in the United States it is mostly fed to young farm animals. In 
some localities, it is used in the manufacture of cheese, or in the 
manufacture of cold water paints and patent foods. A product, 
which is extensively used for sizing paper, is manufactured from 
skim milk. 

41. Q. What function does it perform in the body? 

A. Skim-milk contains all the constituents which furnish food 
for muscle and bone, and in the same form and per cent as that of 
whole milk. It also contains one of the constituents that produce 
heat, namely, milk sugar. 

42. Q. What is buttermilk? 

A. Buttermilk is the residue of the cream after the butter is 
churned. In other words, it is cream with the butter fat taken 
out of it. 



AND DAIRY ARITHMETIC. 9 

43. Q. What is the composition of buttermilk? 

A. Buttermilk is similar to skim-milk except in milk sugar. 
Its composition, however, like that of skim-milk, varies. Average 
buttermilk contains about 9.3 per cent solids, of which 4.6 per cent 
is lactic acid and milk sugar, 3.7 per cent casein and albumen, .3 
per cent butter fat, and .7 per cent ash. Buttermilk, like skim- 
milk, is used for human food, for feeding young animals, and, to a 
small extent, is used in manufacturing buttermilk cheese. It is 
also used for medicinal purposes, and is considered one of the 
most wholesome drinks. 

44. Q. Of what part of milk is cheese made? 

A. Cheese contains a part of all the constituents of milk. The 
percentage of the constituents, however, has been decidedly 
changed. Roughly speaking, a well-cured cheese consists of 33 
per cent water, 33 per cent casein, 33 per cent fat and about 1 per 
cent ash, sugar and lactic acid. As is noticed, cheese, if properly 
manufactured, is one of the richest foods for human consumption. 

45. Q. What is the by-product of cheese? 
A. Whey. 

46. Q. What is the composition of whey? 

A. Whey is composed of about 6.7 per cent of solids, of which 
5 7 per cent is milk sugar, .8 per cent albumen, .6 per cent ash, 
and 3 per cent fat. Whey is not so nourishing as skim milk, since 
it is deprived of most of the albuminoids and fats. It is generally 
used for the feeding of farm animals. 

47. Q. What is condensed milk? 

A. Milk from which one-half to two-thirds of the water of the 
original milk has been removed. Some brands contain about 25 
per cent to 35 per cent of cane sugar in addition to the milk solids. 



DIVISION FIVE. 
Weight and Specific Gravity of Milk and Its Products. 

48. Q. What is the weight of a gallon, quart, or pint of milk? 

A. The weight of milk varies a trifle with its specific gravity, or 
the per cent of solids. The weight of a gallon of milk is about 8.6 
pounds; of a quart, 2.15 pounds; of a pint, 1.07 pounds'; or an 
eight-gallon can should hold 68.8 pounds, or a ten-gallon can 86 
pounds of milk. 

49. Q. What is the weight of a gallon of cream? 

A. The weight of a gallon of cream varies according to its per- 
centage of butter fat. The more butter fat the lighter will be the 
cream; hence, on a commercial basis, it is sold under the three fol- 
lowing weights: (1) Cream that contains less than 20 per cent but- 
ter fat is sold on the basis that one jrallon of cream weighs 8.6 
pounds. (2) If cream contains from 20 per cent to 40 per cent of 
butter fat, it should be sold on the basis of 8.4 pounds per gallon. 
(3) Cream containing from 40 per cent to 80 per cent of butter fat 
should be sold at the rate of 8.2 pounds per gallon, although there 
is only little of this kind of cream on the market. 



10 FUNDAMENTAL DAIRYING 

50. Q. How much does a gallon of skim-milk weigh? 

A. A gallon of skim-milk varies a trifle according to its specific 
gravity, but practically it may be taken as 8.65 pounds. 

51. Q. What is meant by specific gravity? 

A. The specific gravity of a substance is the difference be- 
tween the weight of that substance and the weight of an equal vol- 
ume of distilled water. Water is always considered as one, or the 
unit with which liquids and solids of the same temperature are 
compared; for instance: 

One gallon of water weighs 8.3 pounds; the specific gravity is 1. 
One gallon of milk weighs 8.b' pounds: the specific gravity is 1.032. 
One gallon of butter fat weigns 7.7 pounds; the specific gravity is .93. 

Hence, other conditions being equal, the weight of cream varies 
with its per cent of butter fat. 

52. Q. If the butter fat in milk is lighter than water, what raises the 
specific gravity to 1 032? 

A. It is due to the increased proportion of solids, not fat (such 
as albuminoids, milk sugar, and ash), which are heavier than 
water. 

53. Q. Can you find the weight of a certain volume of any substance if 
the specific gravity is known? 

A. Yes; by multiplying the specific gravity of the substance 
by the weight of water of equal volume. 

EX \MPLE. 

Problem 1. — Cream that contains 10 per cent of butter fat has 
a specific gravity of 1.023 at 60° P. What is the weight of a gal- 
lon of this cream ? 

8.3 (t he weight of a gallon of water) X 1.023, (the specific grav- 
ity) = 8.49. or practically 8 5 pounds. 

Problem 2. — 25 per cent cream has a specific gravity of 1.002. 

8.3 X 1 002 = 8.31, 8.3 pounds. 

54. Q. Why mist the temperature of any substance be the same as the 
temperature at which the specific gravity of water was taken? 

A. Because liquids expand upon heating and contract when 
cooled. A gallon of water at 60° F. will, upon heating to 100° F ., 
increase in volume so that it will occupy more than a gallon; 
hence, it is necessary to keep the same temperature in order to 
calculate the specific gravity of a substance. 



DIVISION SIX. 
Necessity for Testing Dairy Products. 

Method. 

55. Q. What, then, is the just method for buying or selling milk or cream? 

A According to the above answers the proper way to buy milk 
and cream is by weight and the per cent of butter fat, since this con- 
stituent has the greatest marketable value at the present time. 
Nearly all the milk bought from farms by creameries, cheese fac- 
tories and condensing factories is bought by weight, but a much 
smaller amount is bought according - to the butter fat. Retail 



AND DAIRY ARITHMETIC. 11 

dealers, as a rule, still adhere to the old method of buying by 
measure (gallons), yet many of them are establishing arbitrary 
standards, giving the amount of butter fat the milk should con- 
tain. Nearly all the milk and cream that is retailed for direct 
consumption in cities is sold by measure (quarts and pints), since 
the labor that is necessary to weigh into bottles costs more than 
is saved. Pew city dealers guarantee the per cent of fat in milk 
and cream; hence, milk or cream retailed in cities in small quan- 
tities can be justly sold by measure, but the price should be regu- 
lated according to the per cent of butter fat it contains. For 
illustration, milk which contains 3 per cent of butter fat and sells 
for 5 cents a quart is not worth as much as milk which contains 4 
per cent of butter fat, providing the latter is as sweet and pure as 
the former. It is far more important to buy a id sell cream on a 
basis of the butter fat content. Hence, if 20 per cent cream sells 
for 60 cents per gallon, 40 per cent cream should be worth $1 20 
per gallon, providing the cream is of equal purity and sweetness. 

56. Q. Can the quantity of butter fat in milk or cream be regulated? 

A. Yes; the milk or cream should be tested for its butter fat 
content and then standardized according to the per cent desired. 
(See rules for Standardizing.) 



DIVISION SEVEN. 
Testing Milk. 

57. Q. How can you test milk? 

A. By means of the Babcock test. 

58. Q. Can you test other dairy products by means of this tester? 

A. Yes; milk, cream, skiin-milk, buttermilk, whey, cheese, 
and condensed milk. 

59. Q. What advantages are there for knowing the per cent of butter fat, 
other than it serves as a basis for buying and selling milk and cream? 

A. (1 ) One can determine the value of the individual cow. The 
greater the number of pounds of butter fat a cow produces during 
the year, the more valuable is the cow, providing the feed and 
care necessary to sustain her does not overbalance the value of 
butter fat. ' By determining the cost of the amount of feed and 
labor that is required by a certain cow, the cost of the production 
of milk or butter fat can be calculated. (2) One can determine the 
amount of butter fat lost in the skim-milk when separated; also 
the amount of butter fat lost in whey in the manufacture of cheese. 
If the loss is too great, so that the business becomes unprofitable, 
the fault can be readily discovered and remedied. 

60. Q. Is it practical to buy a Babcock tester'.-' 

A. The Babcock tester is as essential in buying milk or cream 
as the scale is in buying corn. 

(31. Q. Does it require much time to test a sample of milk? 

A. No; if everything is in readiness the work can be done in 
ten minutes. However, four or more samples of milk can be 
tested in nearly the same length of time. 



12 FUNDAMENTAL DAIRYING 

METHOD OF OPERATION. 

62. Q. Name the pieces of apparatus which comprise the Babcock tester? 
A. (1) Centrifuge (or whirling machine), (2) graduated Babcock 

milk- test bottle. (3) pipette, (4) acid measure. 

63. Q. Are there any chemicals used in making the test? 
A. Yes; one — sulphuric acid. 

64. Q. What are the different steps in testing milk with the Babcock 
tester? 

A. 1. See that the test bottles and pipettes are accurately cali- 
brated (accurately marked). 

2. See that the test bottles and pipette are clean. 

3. See that the centrifuge is properly oiled and in order before 
starting. 

4. See that the sample of milk to be tested is thoroughly 
mixed. (If a composite sample, follow the details as explained 
below.) 

5. See that the temperature of the sample of milk is not below 
50° P. nor above 70° F. 

6. .Measure out 17.6 cubic centimeters of the milk with the pi- 
pette and put it into the test bottle. 

7. See that the sulphuric acid is of the proper strength (sp. gr. 
1.82.) 

8. Measure out 17.5 cc. of sulphuric acid and put into the test 
bottle with milk. 

9. Thoroughly mix the acid and milk. 

10. Put the mixture into the centrifuge and see that the centri- 
fuge is balanced. 

11. Turn the centrifuge five minutes at the proper speed, then 
add hot water to the mixture until it reaches the 7 or 8 mark on 
the graduated neck. 

12. Put into centrifuge and rotate the bottle two minutes more. 

13. Take out bottle and read it immediately. 

Detailed Explanation of the Babcock Test. 

Calibration (accurate marking-, or graduation) of glassware. 

Exactness in determining the per cent of butter fat in milk re- 
quires, among other things, the correct graduation of test bottles 
and pipettes. Sometimes there is a slight error in one or the 
other, leading to erroneous conclusions. It is therefore always 
advisable to calibrate the glassware used in testing milk. It may 
be done as follows. See that the bottle is thoroughly cleaned and 
dry— especially free from fat. The space in the Babcock test 
bottle between the zero and the ten-per-cent mark holds just two 
cubic centimeters. Pour two cubic centimeters of mercury (by 
weight 27.18 grams) into the test bottle. Insert a smooth cork 
into the bottle until the end reaches the ten percent mark. In- 
vert the bottle. If it is correctly graduated, the mercury will 
just reach the zero mark. 

A more convenient way to calibrate test bottles is by means of 
the N-H milk bottle tester. This tester consists of nothing more 
than a piece of metal of such a size that it will displace exactly two 



AND DAIRY ARITHMETIC. 13 

cubic centimeters of liquid. It is divided into two parts, con- 
nected with a thin wire, and each part displaces one cubic centi- 
meter, which is equal to 5 per cent on the graduated scale of the 
test bottle, or the two parts are equal to 10 per cent. It is used 
as follows: 

Pill the bottle with milk or alcohol (water may be used, but it is 
not recommended owing to its greater capillary attraction to the 
neck) so that its highest point is exactly even with the mark. 
Then slowly lower the tester into the bottle until the liquid rises 
about half way between the two sections, and at that point should 
be the five per- cent mark. 

That point having been established, slowly lower the entire 
tester into the bottle so that the liquid rises over the top of the 
upper section about one eighth of an inch, and if the liquid is ex- 
actly even with the temper cent mark, and was the same at the 
five-per cent mark, the bottle is correct. 

Before using again, the liquid adhering to the tester should be 
wiped off. See that the neck is practically free from adhering 
drops of liquid and that no air bubbles are located between the 
tester and the neck of the bottle. 

Bottles of more than one-tenth of one per cent out of the way 
may be considered unfit tor use. 

The easiest way to calibrate a pipette is to fill it to the mark 
with water, deliver it into a weighed vessel and find the weight of 
the water. This weight should be 17.41 grams. It can also be 
calibrated by dropping 17.4 cubic centimeters of water from an 
accurately graduated burette. 

The acid measure need not be calibrated with extreme accuracy, 
since the strength of the acid and the temperature tend to cause a 
variation in the amount. 

In calculating what quantity of butter fat could be conveniently 
read with the greatest accuracy and with the smallest cost, Doctor 
Babcock estimated that a space in a narrow glass tube holding two 
grams of water and representing 10 per cent of a quantity of milk 
would best meet these conditions. Accordingly, a tube containing 
such a column of water was marked at the base and top of the 
column, and this space was divided into ten equal portions, repre- 
senting per cents. Each division was then divided into five parts, 
each representing two- tenths of one per cent. Since this column 
of water weighs two grams, an equal volume of butter fat would 
weigh 1.8 grams (fat having a specific gravity of approximately 
.9). Then 1.8 grams represents 10 per cent of a certain volume 
which must be 18 grams. Hence 18 grams of milk is the proper 
amount to use in testing for butter fat with the Babcock tester. 

REASON FOR TAKING 17.6 CUBIC CENTIMETERS. 

On account of the inconvenience of weighing, these weights 
have been reduced to their equivalent volumes. Considering the 
average specific gravity of milk as 1.032, the equivalent volume of 
18 grams of milk is found to be nearly 17.44 cubic centimeters; 
e. g., 18 -=- 1.032 = 17.44. Allowing for the small quantity that ad- 



14 FUNDAMENTAL DAIRYING 

heres to the side of the pipette, 17.6 cubic centimeters has been 
taken as the proper amount to be measured out. 

CLEANING TEST BOTTLES AND PIPETTES- 

The test bottles should be emptied of their contents while yet 
hot, in order that the fat may. not stick to the sides. The bottles 
should be well skaken to remove any sediment. A thorough rins- 
ing with boiling water is usually sufficient to complete the cleaning; 
but this is not practical, since it. requires special apparatus to in- 
troduce into the bottle water that is hot enough to do the proper 
cleaning; it is, therefore, safer to use an alkali, such as salsoda or 
caustic potash, or a soap powder, to remove the fat. A little sul- 
phuric acid and bichromate of potassium should be occasionally 
used to insure absolute cleanliness. At times a sediment accum- 
ulates on the bottom and sides of the boUle. This can be thor- 
oughly removed by the use of No. 8 or No. 9 shot Put the shot 
and alkali solution into the bottle and shake violently. By this 
means all sediment, which was not readily dissolved by acid or 
alkali, can be removed. All washing should be followed by a 
rinsing with boiling water and a thorough draining. Boiling 
water following a rinsing with cold water is sufficient, as a rule, 
for cleaning pipettes, but alkalies should be used occasionally to 
remove the grease. 

HOW TO OBTAIN AN ACCURATE SAMPLE OF MILK FROM A COW. 

The first milk given down by a cow is very low in butter fat, 
while the last milk or "strappings" is high in butter fat. For this 
reason it is essential to milk the cow dry rir^t. Then mix evenly 
by thorough Stirling and take a sample from the entire milking. 
If a composite test is to be made, put the sample into a milk jar 
and follow instructions given below. 

SAMPLE FROM A HERD. 

There are two ways to obtain an accurate sample of the milk 
from a herd of cows. First, mix the milk from all the cows to- 
gether and take sample with usual precautions Or. second, take 
equal or aliquot parts of each cow's milk and mix together in one 
sample. 

A COMPOSITE TEST. * 

A composite test is a test made from a number of samples 
which are taken at various times arid mixed together in the right 
proportion, so that the amount of fat it contains is proportional to 
the amount of fat in the quantity of milk that it represents. To 
do this, each sample of milk taken must be an equal or aliquot 
part of each milking or of each quantity of milk. This sample 
can be taken with a brass tube of three-eights to one half-inch 
bore, and the receptacle into which the milk is placed when the 
sample is taken must always be cylindrical and of the same size 
in order to secure the proportional amount of milk. The milk 
should be slightly stirred and the tube lowered into the milk so it 
will take a sample from the different layers of milk. The milk 
may be retained by putting the finger ever the end of the tube; 



AND DAIRY ARITHMETIC. 15 

then place milk in a jar and add a preservative to keep it sweet. 
The preservatives used may be formaldehyde, corrosive subli- 
mate, or bichromate of potassium. The two latter substances are 
poisonous. The quautity of preservatives used varies with the 
quantity of milk to be preserved, and also with the temperature at 
which the milk is kept. About twenty to thirty drops of formal- 
dehyde will preserve a quart of milk for live days at a tempera- 
ture of 60° to 70° P., or 10 grains of corrosive sublimate or 20 
grains of potassium bichromate will preserve the same amount of 
milk at the same temperature. More preservative should be used 
if more milk is added, and if kept at a warmer temperature. Care 
should be taken that the jars are covered and not exposed to too 
much light, for the cream becomes leathery, and this makes it dif- 
ficult to mix into the milk. To take a sample from the composite 
test, the milk must be heated to about 110° F. in order to get a 
thorough mixture of cream and milk. It must then be gradually 
cooled and mixed while cooling. Care must be taken not to churn 
sample. The shaking should be done by a rotary motion. The 
sample must be taken immediately after mixing and tested in the 
regular manner, except where bichromate of potassium has been 
used, in which case a little less acid must be taken in making the 
test. 

HOW TO TAKE A SAMPLE FROM SOUR MILK. 

When milk has become sour, the casein may be redissolved by 
adding an alkali. Powdered potash, soda or liquid ammonia may 
be used. Care should be taken not to use too much alkali as it re- 
acts with the acid and may throw some of the sample out of the 
bottle. It may at the same time cause an error in the sample by 
increasing the volume. The potash and soda may be dissolved in 
water before being used, and a volume. equal to about five per cent 
of the volume of milk will be sufficient to dissolve the casein. 
This amount of solution increases the volume of the milk, and 
thus necessarily decreases the per cent of fat. If the volume of 
milk to be tested is measured and the solvent is also measured, 
the per cent of decrease can be calculated in the following manner: 

Example. — Nine cubic centimeters of alkaline solution has been 
added to dissolve the casein, which is five per cent of the milk 
used (180 : 9 :: 100 : o = 5). The mixture gives a test of 3.9 per 
cent of butter fat. The test must be increased 0.195 per cent 
(3.9 X .05 = 0.195). Hence, the per cent of fat in the original 
milk is 4.095 (3.9 + 0.195 = 4.095). 

ALIQUOT PART. 

An aliquot part is an exact division of any number, or an exact 
per cent of any quantity. For illustration, if a composite test 
sample is started with a rate that one thirty-third part of a hun- 
dred is to be taken as the sample to be tested for the butter fat, all 
other samples for this individual test must be taken in the same 
ratio. For instance, cow No. 1 gives 25 pounds of milk at a milk- 
ing; hence a proportionate quantity representing one-third of one 
per cent, or 25 X .00331 = .08$ pounds. 

At another milking she gives 20 pounds; hence, the same pro- 

—2 



16 FUNDAMENTAL DAIRYING 

portion must be taken, which is 20 X .0033^-, or .06 ]bs. of the sam- 
ple to be tested. In case of taking a composite sample, in a cream- 
ery, where a man brings in 800 pounds one day and 400 pounds an- 
other, he should have exactly the same per cent of the quantity of 
milk in his composite simple bottle as he had in the milk that he 
brought, namely, twice as much in the first as in the second. 

The error made by taking the same quantity for a sample, as is 
commonly done by means of a spoon or any other receptacle, 
where a constant quantity of milk is taken for the sample jar. re- 
gardless of the amount and quality of milk from which it is taken, 
can be proven by a problem. 

A cow produces one day, 50 pounds of milk, which contains 4 
per cent of fat. On the second day she gives but 25 pounds of 
milk which tests 3 per cent of butter fat. If an equal amount 
was taken from these two milkings, such as with a tablespoonful, 
the sample would indicate half 3 per cent milk and half 4 per cent 
milk. The Babcock test would show the average per cent fat of 
the samples which, according to their amounts, would be 3 per 
cent and 4 per cent added together and divided by 2, or 3£ per 
cent. Hence, 3^ times the total quantity, or 75 pounds of milk, 
would amount to 2.625 pounds of butter fat, while if an aliquot 
sample had been taken the amount of fat would be 50 X 4 = 2.00 
and 25 X 3 = .75. Total would be 2.00 + .75 = 2.75, a difference 
of .125 of a pound of fat. 

To obtain the true per cent of butter fat, it becc"aes a problem 
in alligation as, for example, in the preceding problem, 2.75 
pounds butter fat -4- 75 pounds milk = .0366, the aw irage per cent 
of fat in the above quantity of milk. Hence, from the above it 
will be seen that the only just sample that can be secured is by 
taking an aliquot part. This can be done by means of tubes and 
milk receptacles of the same size or relative proportionate sizes. 
The proportional content of a cylinder can be calculated by a for- 
mula 7TR 2 H. 

it = 3.1416. 

R = radius'of cylinder or -k diameter. 

H = height of cylinder. 

Hence the relation between two cylinders of the same height 
varies with the radius. 

SAMPLING FR1ZEN MILK. 

Frozen milk should be heated to 130° F. and then thoroughly 
shaken and gradually cooled in order to incorporate the fat glob- 
ules that have been churned by freezing. 

SAMPLING MILK THAT HAS BEEN CHURNED. 

One method is to dissolve the little lumps of butter fat with 
ether, shake the whole mass and mix into the milk. Another 
method is to heat the churned milk to a temperature of 110° to 
120° F. until the fat is melted; then by shaking and cooling, the fat 
can be remixed with the milk. The sample is thm taken in the 
usual manner. 



AND DAIRY ARITHMETIC. 17 

MIXING MILK TO BE TESTED. 

Milk should be thoroughly mixed so that the fat may be evenly 
distributed throughout the whole mass, and an accurate test pro- 
cured. This mixing should be done by giving the bottle a rotary 
motion, since a violent mixing will cause the butter fat to churn. 
Another way is to pour the milk back and forth from one vessel 
to another. This should not be done more than twice or three 
times, depending somewhat on the consistency of the cream. 
HOW TO MEASURE OFF 17.6 CUBIC CENTIMETERS WITH PIPETTE. 

Immediately after the milk. has been mixed, draw milk into a 
pipette above the mark indicating 17 6 cubic centimeters, then 
suddenly close the upper end of the pipette with the index finger. 
By slightly releasing the pressure, the milk is allowed to run 
down until it reaches the mark, when it is again stopped by press- 
ing finger on pipette. It is then transferred into the test bottle 
and is delivered by holding the pipette at a slight angle in order 
to allow for the escape of the air which is replaced by the milk 
that flows into the bottle. Care must be taken to see that the 
index finger is dry when measuring out milk, and that all milk 
adhering to the pipette is blown into the bottle as thoroughly 
as possible. An exact amount of milk must always be taken. 
Special care must be exercised that milk of a previous sample 
may not be dropped into the bottle; also that no milk adhering to 
the outside of the pipette is discharged into the milk bottle. 

AMOUNT AND KIND OF ACID USED. 

Sulphuric acid, having a specific gravity of approximately 1.82, 
should always be used. The amount needed should be, approxi- 
mately. 17.5 cubic centimeters, depending somewhat on the 
strength of the acid and temperature of the milk. The proper 
temperature of the milk is from 60° to 8(P P. for adding acid. 
If the milk is colder than 60°, more acid must be used. If the 
milk is warmer than 80°, less acid must be used. If the acid is 
too weak, more acid must be used or else the milk must be heated 
higher than 80° P. If the acid is too strong, less acid must be 
used or the milk must be lowered in temperature (below 50° P.). 

If acid is too strong it can be weakened by diluting with dis- 
tilled water. This must be done verj r cautiously, since pouring 
water suddenly into a jug or bottle of acid causes the receptacle to 
heat and burst. A safe way is to fill a small glass three-fourths 
full of acid, then add water until glass is full. This mixture, 
which becomes very hot, should then be set away and cooled grad- 
ually. When cold, the mixture may be turned into the carboy or 
the receiver. The amount of water required depends on the 
strength of the acid. It is best to start with a small quantity of 
water, as, for instance, one-half pipette of water to one gallon of 
acid. 

THE MANNER OF ADDING ACIDS. 

Pour acid into the acid measure until it reaches the 17.5 cubic 
centimeter mark. Transfer the acid into the test bottle, which 
contains the milk, by holding the test bottle at an angle of 45 D and 



18 FUNDAMENTAL DAIRYING 

pouring: the acid slowly so that it will run down the side of the 
neck; at the same time slowly rotating the test bottle so as to 
wash all the milk from the neck of the bottle. 

MANNER OF MIXING ACID WITH MILK. 

The acid, being heavier, flows beneath the milk, and care should 
be taken that the mixing is done within five to seven minutes after 
the addition of the acid, since where the milk is left too long in 
contact with the acid, the casein of the milk becomes charred, and 
rises and mixes in with the fat in the graduated column. The 
mixing should be done by a rotary motion so that the curd will 
not lodge in the neck of the bottle and again influence the reading 
of the butter fat. The graduated portion of the test bottle must 
always be kept clean and free from curd. 

TEMPERATURE OF SAMPLE AFTER MIXING. 

When the acid and milk are added together, the mixture will 
become very hot. This decomposes the solids not fat and facili- 
tates the melting of the fat, and tends to raise the fat more 
quickly. The temperature at which sample should be retained is 
about 130° to 140° F. 

PLACING THE BOTTLE IN THE CENTRIFUGE. 

After mixing, the bottles should be placed in the centrifuge 
(the machine which whirls the bottles) in such a position that the 
centrifuge wheel will retain its equilibrium. A conveninet way to 
do this is to place an equal number of bottles of equal height on 
each side of the wheel. If an odd number is to be tested, till an- 
other test bottle with water. 

THE PURPOSE OF THE CENTRIFUGE. 

A centrifuge is a machine constructed for the purpose of whirl- 
ing the test bottles. The whirling of the bottles and the mixture 
produces a pressure known as centrifugal force. This is illus- 
trated by taking a pail and swinging it arm's length in a vertical 
circle. If the pail is kept in motion, the water will not spill out 
even though the pail is in an inverted position. The reason this 
water does not spill out is due to the outward pressure, or centrif- 
ugal force. The heavier particles will go nearest to the outside 
(because their own weight produces a greater force) and crowd 
the lighter portions toward the center. The tendency of all parti- 
cles of matter is to arrange themselves according to their weight, 
when acted upon by centrifugal force. Another illustration may 
be found in a piece of lead and a piece of cork of equal size. Tie 
each to a string of equal length and whirl them. Upon whirling 
it is found that the pull of the piece of lead is much greater than 
that of the cork, because it is heavier. Pat is the lightest con- 
stituent of the mixture of milk and acid in the test bottle, and for 
this reason it is crowded to the top, or separated out by the 
heavier particles by centrifugal force produced by whirling the 

centrifuge. 

The Speed of the Centrifuge. 

The centrifugal force of the centrifuge depends upon the diam- 
eter and velocity of the wheel. It is estimated that enough 



AND DAIRY ARITHMETIC. 19 

force must be generated to equal 30.65 pounds pressure on each 
bottle. The centrifugal force is increased directly in proportion 
to the increase in the diameter and directly with the square of the 
velocity of the centrifuge. 

FORMULA FOR CALCULATING THE SPEED OF THE CENTRIFUGE WITH 

A GIVEN DIAMETER. 

F = Centrifugal force (30.65). 

W = Weight of bottle and contents (A of a pound). 
V = Velocity in feet per second. 
R = Radius of wheel in feet. 
To find velocity in feet per second : 

v _ diara. in ft. X 3.1416 X No of revolutions per min. 

How to find speed required to obtain necessary centrifugal 
force: 



T7 . ., J 32 2 X F X R , 

Velocity = yj x = i/526iR 

1 6 



which equals velocity in feet per second. 

To find the revolutions of wheel per minute: 

60V V = velocity in feet per second. 

27rR = 2 X. 3.1416 x radius in feet. 

Example — How many turns should be given the handle of a 
tester to produce the proper centrifugal force, when the wheel is 
16 inches in diameter? 



V 



/32.2F X R 



Substitute the value for F and W. 



32.2 X 30.60 R , 

V = \l , = i/5264 R 

16 

Substitute the value for R or radius in feet. 

V - 1/5264 X % = 59.24 

To find the number of revolutions after the velocity in feet per 
second is found, apply the following formulas: 

Rev. = 60 V 



277-R 

Substitute the value for V and R. 

Rev. = 60 x 59.24 = 855; or number of revolu- 
2 X 3.1416 x f 

tions of the centrifuge wheel per minute. 



20 FUNDAMENTAL DAIRYING 

Find the corresponding 1 number of revolutions of the wheel, to 
that of the handle turning it once around, and count the number 
of revolutions the wheel of the centrifuge has made, supposing it 
revolved 10 times. Divide this number by the number of revo- 
lutions the wheel made per minute (- 8 T 5 ^ 5 - = 85.5), which is the 
number of turns required at the handle to produce the necessary 
centrifugal force. 

Diam. of wheel Rev. of wheel 

in inches.* per minute. 

10 1074 

12 980 

1-1 909 

16 840 

18 800 

20 759 

22 724 

24 693 

THE LENGTH OP TIME OF FIRST RUN. 

The centrifuge should be run for five minutes at the regular 
speed calculated by the above formula to produce the proper force 
required to separate the fat perfectly from the mixture. Care 
should be taken that the above speed of the centrifuge is kept up 
for the required length of time. If, for any cause, the speed 
should slacken, the fat will not separate thoroughly, and the read- 
ing will be too low. 

ADDING WATER TO THE TEST. 

After the first run, add hot water and fill the bottle until the 
level of the water reaches the seven- or eight-per-cent mark. 

TIME AND PURPOSE OP THE SECOND RUN. 

After adding hot water, the bottle is put into the centrifuge and 
given a second run of two minutes more. The water must be ap- 
proximately of 140° P. temperature if tested in a steam turbin 
centrifuge, or a temperature of 160° to 180° P. if tested with the 
hand tester. The hot water keeps the fat in liquid form and tends 
to facilitate the rise of the fat to the top of the water, and at the 
same time causes the fat and the water to separate definitely, 
leaving a clear line of distinction. Distilled water is the best to 
use for this purpose; if not at hand, boiled water should be used 

APPEARANCE OF THE TEST. 

The fat column in the neck of the bottle should have a clear, 
yellowish and uniform appearance. Specks or sediment indicates 
a wrong manipulation at some point, or it may indicate that some 
foreign material has been added to the milk before, or at the time 
it was tested. 

Foam on the fat column usually indicates the presence of a 
small amount of alkali in the water that has been added to bring 
the fat up in the column. This can be eliminated by adding a 
drop of alcohol after the test is completed. 



♦According to Tarriogton. 



AND DAIRY ARITHMETIC. 21 

THE CAUSE OP A CHARRED TEST OR BLACK FAT IN THE BOTTLE. 

This is caused by too much heat, which is due to the acid being 
too strong or the milk heated to too high a temperature before the 
acid is added; or the mixture of acid and milk was kept at too 
high a temperature for some time after mixing, or kept too long 
in a hot centrifuge. 

CAUSE OF A WHITE OR CURDY APPEARANCE OF FAT. 

This is due to insufficient heat caused by the temperature of milk 
being too low before acid is added, or acid being too weak; or the 
test was kept too cool during the operation. 

HOW TO DETERMINE THE PROPER AMOUNT OF ACID REQUIRED FOR 

TESTING MILK. 

Take three or four test bottles with milk of the same quality 
and temperature. Use various amounts of acid in the different 
bottles and test each bottle under the same condition and note 
which quantity gives clearest fat column, and this will be the 
proper amount required. 

READING THE FAT COLUMN. 

The per cen 3f fat is read by counting the spaces between the 
lowest point of vbe lines of separation of the fat and the water and 
the extreme upper part of the fat miniscus. 

Experience and comparison with the gravimetric analysis 
shows that enough fat is left in the bottle to till up the two spaces 
not filled with fat, caused by the capillarity of the fat and glass. 
Prom these extreme points the correct reading of fat in the milk 
is indicated. 

HOW TO CALCULATE THE POUNDS OF BUTTER FAT IN MILK WHEN 
THE PER CENT OF FAT IS KNOWN. 

The readings of the bottle indicate per cent. The per cent of 
butter fat in milk represents the number of hundredth parts of 
the whole quantity of milk. To find the amount of butter fat, 
multiply the per cent of butter fat by the pounds of milk and di- 
vide by one hundred. The product will equal the pounds of but- 
ter fat; thus: 144 pounds of milk testing three per cent butter 
fat, 144 X .03 = 4.32 (pounds of butter fat). 

CARE OF THE CENTRIFUGE. 

The centrifuge should always be kep 1 : clean and well oiled; it 
should be fastened to a solid foundation and should stand level so 
that it may run in perfect balance. If a steam turbin, it should 
have the exhaust open large enough for the exhaust steam to 
escape easily. Caution should be taken that the steam does not 
come in too direct contact with the bottles, for high heat intro- 
duces an error in the reading of the fat. 

HOW TO PROVE THE CORRECTNESS OF A TEST. 

The correctness of a test may be proven by testing duplicate 
samples. If the reading in the two samples is the same, it is al- 
most certain to be accurate, providing the manipulations have 
been followed strictly according to these details. 



22 FUNDAMENTAL DAIRYING 

MARKING THE TEST BOTTLES. 

In testing two or more samples, it is necessary to mark the bot- 
tle which corresponds to the sample it contains. For this purpose 
nearly all Babcock test bottles have an etched portion either at 
the neck or on the bulge of the bottle. In case a bottle is not 
etched, the operator can easily etch it by applying hydrofluoric 
acid. The bottle can then be marked on the etched portion with, a 
lead-pencil. 

DIVISION EIGHT. 

TESTING SKIM-MILK, BUTTERMILK AND WHEY. 

64. Q. Why is skim-milk tested? 

A. Skim milk is tested for its butter fat, to show how much 
has been lost by skimming or separating the cream from the milk. 
Other things being equal, the best system of skimming is that 
which leaves the least amount of butter fat in the skim-milk. 

Examples. — ( I) The average skim-milk that is skimmed by the 
shallow-pan system contains from .6 per cent to. 7 per cent of but- 
ter fat. (2) The average skim-milk from the deep setting system 
contains from .4 per cent to .5 per cent of butter fat. (3) The av- 
erage skim-milk from the centrifugal system (cream separator) 
contains about .1 per cent butter fat. Hence, it will be seen that 
the centrifugal method of separation is far more efficient than 
either of the other methods. 

6"). Q. Is money well invested in purchasing a cream separator with the 
above saving over the shallow-pan system? 

A. This depends somewhat upon the quantity of milk to be 
separated, which directly depends upon the number of cows. 

Example. — An average cow produces 5000 pounds of milk a year. 
If .5 of one per cent is saved by the centrifugal system over the 
shallow pan system, it means that there has been recovered 5000 
times .005, or 25 pounds of butter fat, which will make about 29 
pounds of butter. Twenty-nine pounds of butter at 22 cents 
equals $6.38, the amount saved in one year, which amount indi- 
cates 10 per cent on an investment of $63.80. This saving be- 
comes large in a creamery in which a considerable amount of milk 
is handled. 

EXAMPLE. 

66. Q. What is the saving in butter fat of a creamery handling 10,000 
pounds of milk per day, by the centrifugal method (or cream separator) over 
the shallow-pan system, calculating that the saving is .5 of one per cent of 
butter fat in the skim-milk? 

A. 10,000 X .005 = 50 pounds of butter fat per day, or about 58 
pounds of butter, which, if sold at 20 cents a pound, equals $11.60, 
the saving foroneda t y. A creamery operates 365 days; the saving 
therefore amounts to $4,230.00 in a year, which amount represents 
10 per cent of an investment of $42,300.00. 

67. Q. Of what importance is it to know the per cent of butter fat in 
buttermilk? 

A. For the same reason that it is necessary to know the per 
cent of butter fab lost in the skim-milk. It is estimated that the 



AND DAIRY .ARITHMETIC. 23 

average buttermilk produced on the farm contains from one to one 
and a half per cent of butter fat. With science applied to churn- 
ing, this per cent of fat can easily be reduced to. 2 of one per cent. 
To illustrate the loss that occurs by inefficient churning, we will 
say that a cow produces 5,000 pounds of milk, which contains on 
an average 4 per cent of butter fat. If the cream skimmed from 
this milk contained 20 per cent of butter fat, there would have 
been about 980 pounds of cream, providing the loss in the skim- 
milk was not over .1 of one per cent. If the average loss of the 
buttermilk on the farm is 1.2 per cent, the amount that can be 
saved through efficient churning would be one per cent (980 
pounds of cream minus 233 pounds cf butter equals 747 pounds 
of buttermilk), or 7.5 pounds butter fat. which would make about 
8.7 pounds of butter, which, if sold at 22 cents, equals $1.91, the 
loss for one year. 

68. Q. Of what importance is it to know the per cent of butter fat in whey? 
A. For the same reason as in buttermilk — to determine the 

amount of fat lost in the manufacture of cheese. 

69. Q. How can you test skim-milk, buttermilk, and whey? 

A. Skim-milk, buttermilk and whey can be tested with the Bab- 
cock tester, and with the same manipulation as in testing the but- 
ter fat in whole milk, except that a trifle more sulphuric acid is 
added (making 18 c. c. ) and the sample should be run in the centri- 
fuge for eight minutes instead of five minutes. The reading of 
the fat with the common milk bottle in the case of these by prod- 
uts is very unsatisfactory, hence, skim milk bottles, made espe- 
cially for this purpose, have been put on the market These are 
constructed with two tubes, one for pouring acid and milk into the 
bottles and the other for reading the column of fat. This second 
tube is very fine, the whole column of ten marks representing 
only one half of one percent, or one mark representing .05 of one 
per cent. To do accurate work, a skim-milk test bottle should al- 
ways be used for testing the above by-products. 



DIVISION NINE. 
TESTING CREAM. 

70. Q. Is it of great importance for any farmer that produces milk to 
know how to test cream? 

A. It is very essential, if he sells cream; and this will probably 
be the way to sell butter fat to a creamery in the future. 

71. Q. What difference is there in testing cream and milk with a Babcock 
test? 

A The operation is the same, except that the sample of cream 
should be correctly weighed into a test bottle rather than meas- 
ured in with a pipette. There are three reasons why cream 
should be weighed rather than measured in a test bottle. 

First, the Babcock test bottle has been so graduated that a 
sample to be tested should weigh 18 grams. Cream is lighter 
than milk, and thus a larger volume is required to weigh 18 
grams. Hence, the pipette that is graduated to 17.6 cubic centi- 



24 FUNDAMENTAL DAIRYING 

meters, and which will discharge 18 grams of milk, will not dis- 
charge 18 grams of cream. The greater the per cent of fat in 
cream, the greater will be the error in the per cent of fat by the 
use of the pipette. This can best be illusti-ated by a bushel of 
wheat which weighs 60 pounds. Fill the bushel measure with 
oats and you will find that it weighs 32 pounds. Comparing the 
bushel measure with the pipette, the wheat with the miik, and the 
oats with the cream, it will readily be seen that it is impossible to 
get 60 pounds of oats into one bushel measure. Neither can 18 
grams of cream be put into a 17.6 cubic centimeter pipette. 

Second, cream is apt to incorporate a great deal of air, and this 
again decreases the weight per volume. 

Third, cream is also thicker or more viscous than milk, and 
when drawn into the pipette and discharged a considerable quan- 
tity will adhere to the pipette and lessen the weight of the cream 
discharged into the bottle. Hence, for accurate work, especially 
if heavy cream is to be tested, it is necessary always to weigh 
the sample. 

The amount to be weighed out into a test bottle does not neces- 
sarity have to be 18 grams. Any quantity can be weighed out, 
providing the per cent is calculated on an 18-gram basis. 

Example. — The weight of the cream in the test bottle is 6.5 
grams. After testing it is found that the sample contains 8.2 per 
cent of butter fat. The sample of cream on an 18-gram basis 
would contain 8.2x18, or 147.6-^-6.5 = 22.7 per cent of butter fat. 

72. Q. If a smaller quantity of cream is weighed into a test bottle, is it 
necessary to take a smaller amount of acid? 

A. The amount of cream in the test bottle should always be 
diluted with water to about 18 grams weight. 

Example. — If 8 grams are weighed into a test bottle, the differ- 
ence between 8 and 18, or 10, grams of water should be added, 
after which the same amount of acid should be used as in testing 
milk. The 10 grams used need not be weighed out, but only 
approximately measured into the bottle. The water that is to be 
added to the cream must have a temperature of about 60° to 70° 
P. and should be distilled. 

73. Q. How can you overcome the cloudiness in the butter fat column 
which frequently occurs in testing cream. 

A. It is frequently necessary, in order that the fat column in, 
the test bottle comes up clear, instead of filling up the bottle three- 
quarters or more on the graduated scale with water after the first 
five minutes run, to fill the bottle only to the neck. Then by re- 
shaking the fat, mixing it slightly with the acid below, the impur- 
ities are brought down and the fat becomes clear. Instead of run- 
ning the Babcock tester for two minutes in the second run, run it 
three minutes, then stop and add water high enough in the neck 
of the bottle so that the fat can be properly read; after this run 
again for one minute. If the acid is not too strong or too week, or 
the cream is not too cold or too warm, the fat will come up clear. 

74. Q. Can you use a milk bottle for testing cream, or is it necessary to 
have a special bottle for this purpose? 



AND DAIRY ARITHMETIC. 25 

A. Cream can be tested with a whole-milk bottle, but with a 
certain amount of inconvenience. First weigh out 18 grams of 
cream, and add to this 36 grams of distilled water; then by taking 
18 grams of the mixture, the per cent of fat can be determined by 
multiplying the per cent of fat in the bottle by three. 

Example. — If the mixture tests 8 per cent and 36 grams of dis- 
tilled water has been added to the original cream, the actual per 
cent of fat in the cream would be 3 x 8, or 24 per cent. Fifty-four 
grams can be added and the result multiplied by 4; or even 72 
grams can be added and the result multiplied by 5. Multiply the 
test by the number of times it is diluted. Ordinarily a special 
cream bottle is used for testing cream. This bottle has a greater 
capacity in the neck and is hence graduated to a greater scale. 
There are two kinds of cream bottles on the market. One is 
known as the "bulb-necked" cream bottle, which is graduated in 
two tenths per cent marks to 25 per cent of fat. The neck of the 
bottle is shortened by means of the bulb, which has a capacity of 
10 per cent of butter fat. Care must be taken, in filling this bot- 
tle, that the top or bottom level of the fat column does not extend 
into the bulb, since there is no graduation on the bulb. The 
other cream bottle is known as the "Winton Cream Bottle" and 
has a neck of usual length and sufficiently wide to measure thirty- 
five per cent. The scale of the neck is divided into half per cents, 
but readings of a quarter of one per cent can easily be estimated. 

75. Q. Does the diameter of the neck of the tube effect the reading of the 
fat? 

A. Yes. Owing to the fact that the capilary attraction of fat 
and glass is proximately the same height, regardless whether it is 
a small or large tube, there will be an error, due to the different 
graduation which varies with the diameter, if read from the ex- 
treme top to base of the fat column. Therefore, it is preferable 
to use narrow-neck bottles for testing cream. If a wide bottle is 
used the fat column should be read from the fat level rather than 
from the top of meniscus. 

DIVISION TEN. 

7ti. Q. What is meant by standardizing milk or cream? 

A. To standardize milk is to bring the butter fat content to a 
given per cent regardless of the quality of milk produced by the 
cow. If the milk as drawn from the cow contains less butter fat 
than is desired, it can be brought to the desired standard by add- 
ing cream or extracting some skim-milk. If, on the contrary, 
milk that is yielded by the cow contains more butter fat than is 
necessary, it can be reduced to the desired standard by extract- 
ing cream or adding skim- milk. 

77. Q. Is it just to standardize milk? 

A. These processes are not only legitimate, but necessary — 
first in the interest of the consumer, and second in the interest of 
the producer, because the latter can not afford, for example, to 
produce milk containing five per cent butter fat and receive pay 



26 FUNDAMENTAL DAIRY TNG 

for milk which contains only four percent butter fat (providing 
they are produced under equal sanitary conditions). 

78. Q. Can this reduction of fat not be secured by the addition of water? 
A Yes. But this is not permissible, for it also reduces the 

percentage of the solids not fat; that is, casein, milk sugar, and 
ash ; whereas standardizing with cream or skim-milk does not 
materially alter the proportion of solids other than butter fat. 

79. Q. Is there a definite standard to which milk or cream is standardized ? 
A. The butter fat in milk or cream is increased or decreased to 

an arbitrary per cent or standard which may be fixed by law or an 
agreement between parties in which one guarantees to furnish the 
other with a definite quantity of butter fat in every pound of milk 
or cream sold for a stated price. This price should vary with the 
per cent of butter fat in the milk — the more butter fat for the 
same quantity of milk the higher the price, and vice versa. This 
is not only because the richer milk is more nutritious and more 
palatable, but also because the cost of production is greater. 

80. Q. How can the fat in milk or cream be reduced? 

A. If milk contains a higher per cent of butter fat than is de- 
sired, this fat can be reduced either by separating the cream out 
of a portion of the milk or by adding skim- milk. In case all the 
milk is separated for clarification, the same result may be obtained 
by mixing with the skim-milk a smaller portion of the cream than 
was contained in the original milk. Again, there may be an in- 
stance in which no skim- milk is on hand, but instead, an ample 
supply of milk with a lower per cent of butter fat than is desired. 
This milk will answer the same purpose as skim milk, but a larger 
proportion is required to bring the per cent down to the proper 
standard. 

81. Q. How can the fat in milk or cream be increased? 

A. Milk of a lower per cent of fat than is desired may be stand- 
ardized by taking out a portion of the skim-milk by means of a 
separator, or by adding reserved cream; or, as in the above case, 
if the milk is separated for clarification, by mixing with the skim- 
milk a greater portion of cream than there was in the original 
milk. Here, as in the above instance, if circumstances should 
arise in which there is no cream on hand, but instead, milk of a 
higher per cent of butter fat than the desired standard, this will 
then answer the same purpose for increasing the percentage of 
fat to the proper standard. 

82. Q. How can you determine the amount of skim-milk to be added or 
removed from the whole milk to obtain the desired per cent of butter fat? 

A. According to the following rules: 

RULES FOR STANDARDIZING UNDER DIFFERENT CONDITIONS ARE 

AS FOLLOWS: 
RULE I. 

Multiply the number of pounds of milk by the per cent of fat 
in the milk and the product will be the number of pounds of but- 
ter fat in the milk. Divide the number of pounds of butter fat in 



AND DAIRY ARITHMETIC. 27 

the milk by the decimal representing the desired per cent of fat, 
and the quotient will be the number of pounds of standardized 
milk.* 

Part 1. Where the Percentage of Fat is too High. — From the num- 
ber of pounds of standardized milk take the number of pounds of 
original milk and the result will be the number of pounds of skim- 
milk to be added to the original milk. 

To illustrate: 1000 pounds of milk containing 4.5 per cent of 
butter fat are to be standardized to 4 per cent; how many pounds 
of milk must be added? 

Since 4.5 per cent equals the decimal .045 then, 

1000 x 045 = 45, the number of pounds of fat in 1000 pounds 
of 4.5 per cent milk. 

45h-.04 = 1125, the number of pounds of 4 per cent or stand- 
ardized milk. 

1125 -4- 1000 = 125, the amount of skim-milk to be added. 

To formulate this problem: 

A : 1C00::4.5 :4 

A = the pounds of standardized milk. 

B = 1000 x 4.5 _ 100Q . 
4 

B = the number of pounds of skim milk to be added. 

Part 2. Where the Percentage of Fat is too Low. — With milk that is 
to be standardized from a lower to a higher per cent the same rule 
holds true; but in this case take the number of pounds of stand- 
ardized milk from the number of pounds of original milk and the 
result will be the number of pounds of skim milk to be removed 
from the original milk. 

To illustrate: 1600 pounds of milk containing 3 2 per cent of 
butter fat are to be standardized to 4 per cent; how much skim- 
milk must be taken from the whole milk? 

1600 x .032 = 51.2, the number of pounds of butter fat in the 
original milk. 

51.2 -=-.04 = 1280, the number of pounds of standardized milk. 

1600 — 1280 = 320, the number of pounds of skim milk to be 
separated from the original milk, or 

A = 15*°*^ = 1280. 
4 

A = the number of pounds of standardized milk. 

B = 1600 — 1280 = 320. 

B = the number of pounds of skim-milk to be removed. 

RULE II. 

The same results may be reached by the following rule, which 
is often more convenient than the one above given. Divide the 
per cent of butter fat that is in the original milk by the per cent 
that is desired in the standardized milk. The quotient multi- 



*This answer is sufficiently accurate for ordinary practice. As a matter of fact, the 
amount of butter fat in the creurn to be standardized is less than the amount of butter fat in 
the milk, on account of some butter fat left in the skim-milk by separating. Again, when 
skim-miik is added, better fat is also added, the amount depending upon the amount of skim- 
milk added and the per cent of fat contained therein. 



28 FUNDAMENTAL DAIRYING 

plied by the given number of pounds of milk will be the amount 
of standardized milk. If the quantity of standardized milk is 
greater than the original amount of milk the difference must be 
added in the form of skim-milk; if less then that difference must 
be separated out as skim- milk. 

Part 1. Where the Percentage of Fat is too High. — To illustrate : 200 
pounds of milk containing 6 per cent of fat are to be standard- 
ized to 4 per cent; how many pounds of skim-milk must be added? 

.06 -r- .04 ■ = 1.5, hence 200 pounds of 6 per cent milk must be 
increased by one-half with skim-milk, or to 300 pounds. The dif- 
ference between 200 pounds and 300 pounds is the amount of 
skim-milk that must be added, or 

A = '— X 200, in which A = final amount of standardized milk. 

Part 2 Where the Percentage of Fat is too Low. — To illustrate: 
652 pounds of milk containing 3.1 per cent of butter fat are to be 
standardized to 4.5 per cent; how many pounds of skim-milk must 
be extracted? 

3.1 -r- 4.5 = .691, or the fractional part of 652 pounds of 3.1 per 
cent milk to which the amount must be reduced in order to have 
the milk contain 4 5 per cent butter fat. 

652 X -691 — 450, the number of pounds of 4.5 per cent milk. 

652 — 450 = 202, the number of pounds of skim-milk to be re- 
moved, or 

3 1 

A = -—=, X 652, in which A = final amount of standardized milk. 
4.5 

RULE III. 

Occasionally there may be a quick demand for milk of a per 
cent of fat which is not commonly produced, as is often the case 
with city dairy companies. However, milk of a known standard 
is always on band. In this case a definite quantity of milk is 
wanted and the exact proportions of milk or cream to be added to 
the skim- milk may be calculated in percentage or amount as 
follows : 

Divide the per cent of fat in the milk that is desired by the per 
cent of fat in the milk that is on hand. The result will be the 
per cent of the mil'k on hand to be taken; the remaining per cent 
of milk will be the skim-milk to be used. 

To illustrate: 120 pounds of milk containing 4 per cent of but- 
ter fat is desired and milk of 6 per cent fat and skim- milk are on 
hand to be used. What per cent of the standardized milk must be 
milk with 6 per cent fat and what portion .must be skim-milk; 
that is, how much of each must be taken in order that the mixture 
may be 4 per cent milk ? 

.04 -~ .06 = .66f or 66f per cent, which is the portion of 6 per 
cent milk that the 120 pounds of standardized milk should contain. 
The remaining 33^- per cent must be skim-milk which it is neces- 
sary to add to bring- the fat down 4 per cent. 

66f per cent of 120 pounds = 80 pounds, the amount of 6 per 
cent milk which must be mixed with 40 pounds of skim-milk to 
bring the mixture to 120 pounds of 4 per cent milk. 



AND DAIRY ARITHMETIC. 



29 



RULE IV. 

Part 1. — The actual number of pounds instead of the per cent of 
the different kinds of milk to be added may be ascertained as fol- 
lows : Multiply the number of pounds of standardized milk de- 
sired by the per cent of butter fat that the milk is to contain. 
This gives the number of pounds of butter fat. in the mixture. 
Divide this amount by the per cent of butter fat contained in the 
milk on hand and the result will be the number of pounds of that 
milk which the standardized milk should contain. The remainder 
would be ski mm ilk. 

To illustrate: 50 pounds of milk containing 3 per cent fat is 
wanted, and milk containing 5 per cent fat is to be used. 

50 x .03 = 1.5, the number of pounds of butter fat in the 3 per 
cent milk. 

1.5-5- .05 = 30, the number of pounds of 5 per cent milk which 
the standardized milk should contain. 

50 — 30 = 20, the number of pounds of skim-milk to be added. 

Part 2. — In case there is no whole milk on hand but instead 
skim-milk and cream of a known per cent of butter fat, then the 
cream may be substituted and the fat reduced to the desired per 
cent with skim milk. The proportionate amounts may be calcu- 
lated as in the two foregoing methods. 

To illustrate: To make 50 pounds of milk containing 3 per cent 
of fat or 1.5 pounds of butter fat as in the above illustration. If 
25 per cent cream is to be substituted for 5 per cent milk then the 
standardized milk would have to contain 6 pounds of 25 per cent 
cream and 44 pounds of skim milk. 

As a matter of convenience the results of the above rules calcu- 
lated on the per cent or 100 pound basis can be tabulated in such 
a manner as to reduce the calculation to a minimum. 

Table 1 Indicates Quantity of Skim- Milk to be Added to or 

Subtracted from 1G0 Pounds of Milk to Make 

the Desired Per Cent. 



*A 


3. 28 


3.50 


3.75 


4.0 


4.25 


4.50 


4.75 


5.0 


t « 
3.0 


— 7 (593' 


—14.285 


—20.000 


—25.000 


—29 412 


—33 333 


—36 842 


—40. COO 


3.1 


— 4 616 


— 11 423 


— 17.333 


—22.50 


— .'7.059 


—31.111 


—34.737 


—38 000 


3.2 


— 1.539 


- 8.571 


— 14.666 


—20.000 


—24.706 


-28 >8K 


—32.632 


—36 000 


3.3 


+ 1.539 


— 5.714 


— 12..000 


—17.50 


—22 353 


—36 666 


—.50 5.7 


—34.000 


3. -1 


+ 4.010 


— 2.857 


— 9.333 


— 15.00 


—30.000 


-21.444 


—28. 22 


—33.000 


3.5 


+ 7.693 


— 0.000 


— 6.(566 


— 12 50 


— 17.647 


—22 222 


—2(5.317 


—30 000 


3.6 


+10 760 


+ 2.857 


— 4.000 


— 10.00 


— 15.-94 


—20 000 


-34.313 


—28.000 


3.7 




+ 5.714 


— 1 333 


— 7.50 


— 13.941 


—17.777 


—33.107 


—26 coo 


3 8 


f-16.914 


+ 8 571 


+ 1.333 


— 5.00 


— 10.5 8 


—15.555 


—20.000 


—24 000 


3.9 


+19.991 


+ 11.428 


+ 4.0U0 


— 2.50 


— 8.335 


— 13.333 


-17.897 


—23.0(0 


-1.0 


+23.068 


+ 14 285 


+ 6 666 


— 0J 


— 5.882 


— 11 111 


— 15 792 


—20.000 


4.1 


4-26.145 


+17.143 


+ 9.333 


+ 2.50 


— 2.429 


— 8.888 


—13.687 


—18.000 


4.2 




+19.999 


+ 12.000 


+ 5.00 


— 0. 076 


— 6.666 


—11.582 


—16.000 


4.3 




+22.856 


+14 666 


+ 7.50 


+ 0.076 


— 4 444 


— 9.477 


—14.000 


4.4 


+35. 376 


+25.713 


+17.333 


+ 10 00 


+ 2.429 


;_>. g22 


— 7.372 


—12.000 


4.5 


+38.453 


+28.57 


+20.000 


+ 13.50 


+ 5.882 


— 0.000 


— 5.267 


— 10.0<0 


4.(5 


+41 530 


+31.427 


+22.666 


+15.00 


+ 8.235 


+ 2.222 


— 3.162 


— 8.000 


4.7 


+4 4 607 


-4-:;4.-:s4 


+25.333 


+17.50 


+10.588 


+ 4 444 


- 1.057 


— 6.000 


4.8 


+47.684 


+37.141 


+28.000 


+20.00 


+ I2.S'41 


+ 6.666 


+ 1 .057 


— 4.000 


4.9 


+50 761 


+39.998 


+30.666 


+22.50 


+17.647 


+ 8.888 


+ 3.162 


— 2.000 


5 


5:<.838 


43 855 


33 333 


25 000 


20.000 


11. Ml 


+ 5.267 


— 0.000 



*Top line A represents the per cent or fat that is desired in mill*. 
tLef t-hand column B represents the per cent of fat in milk on hand. 



30 FUNDAMENTAL DAIRYING 

To find the pounds of skim milk to be added or removed, trace 
the vertical column of the per cent of fat you desire down to 
where the horizontal column representing the per cent of fat in 
the milk on hand intersects and the result will be the number of 
pounds of skim-milk to be added or removed, as indicated by a 
plus or minus sign before the result. 

To illustrate: If milk containing 4.5 per cent is desired and 
milk containing 3.8 per cent fat is on hand, then 15.5 pounds for 
every hundred pounds or 15.5 per cent of the quantity must be 
separated out as skim-milk. 

To Standardize with Whole Milk or Cream Instead of 

Skim-milk, 
rule v. 

Part 1. — An instance may occur in which milk is to be raised to 
a higher per cent with milk of a still higher per cent of butter fat. 
The quantity to be added may be found in the following manner: 
From the desired per cent of fat in the standardized milk subtract 
the per cent of fat in the milk that is on hand which contains the 
lower per cent of fat. Subtract the per cent of fat that is desired 
in milk from the per cent of fat in the milk that is on hand which 
contains a higher percent of butter fat. Divide the difference 
between the lower per cent and the per cent desired by the differ- 
ence between the higher per cent and the per cent desired. The 
quotient will be that part of any given quantity of milk containing 
the higher per cent that should be taken. Multiply the quotient 
by the quantity of milk of the lower per cent. This will equal the 
quantity of milk of the higher per cent to be added to the milk of 
the lower per cent and the sum will equal the amount of the mix- 
ture containing the desired per cent. 

To illustrate: Standardize 200 pounds of milk containing 3 per 
cent butter fat to 4 per cent fat with 5.2 per cent milk; how many 
pounds of the latter must be added to bring the fat up to 4 per 
cent? 

.04 — .03 = .01. 

.052 — .04 = .012. 

.01 -=- .012 = 833. 

200 X -833 = 166.6, the number of pounds of 5.2 per cent milk 
to be added. 

200 + 166.6 = 366.6, the number of pounds of 4 per cent milk to 
be used. 

p ar t 2. — To standardize milk of a higher per cent than is desired 
with milk of a lower per cent of fat, the same rule applies except 
that the difference between the desired per cent and the higher 
per cent must be divided by the difference between the desired 
per cent and the lower per cent of butter fat. 

To illustrate: 54 pounds of milk containing 5.3 per cent of but- 
ter fat are to be standardized to 4 per cent with milk containing 
3.1 per cent butter fat; how many pounds of the 3.1 per cent milk 
will be required? 

.053— .01 =.013 

.04—031 =.009 

.013 -h. 009 = 1.44. 



AND DAIRY ARITHMETIC. 



31 



54 x 1-44 = 77.76, the number of pounds of milk containing 3.1 
per cent of fat to be added to the 54 pounds to decrease the fat 
content to 4 per cent. 

RULE VI. 

To find the ratio of the number of pounds of milk of the differ- 
ent per cents, subtract the per cent of fat in the milk of the lower 
fat c intent from the per cent of fat desired in the standardized 
milk and divide this result by the difference between the fat per 
cents in the milk of the higher fat content and the lower fat con- 
tent, the quotent represents the per cent of milk of the higher fat 
content to be used in standardizing. 

To illustrate: Find the ratio of the pounds of milk for mixing 5 
with 3.5 to give 4 per cent milk. 

4 — 5.5 =.5 

5 — 3.5 = 1.5 

.5 -=- 1.5 = .33^ or 33^ per cent which is that part of the stand- 
ardized milk containing 5 per cent, which is used in mixing with 
milk of 3.5 per cent fat content. Supposing 400 pounds of milk 
of 4 per cent butter fat is desired then 33^ per cent of the 400 
pounds or 133.3 pounds are to be milk containing 5 per cent but- 
ter fat and 400 — 133.3 = 266.6, the number of pounds of milk of 
3.5 percent butter fat that are to be taken to bring the fat content 
to 4 per cent. 

Where whole milk is used for standardizing the results can be 
tabulated equally as well as when skim-milk is used. In this case 
the whole milk has a constant per cent in each table. 

Table 2. To Standardize Cream with Milk Containing 4 
Per Cent of Butter Fat. 



*A 


17 


20 


22 


25 


27 


30 


tH 

18 


92.857 

86 666 

81.250 

76.4706 

72.2222 

68.4222 

65 OCOO 

61.9ii5 

59.090* 

56.5217 

54.1666 

52/J0O0 

50.0000 












19 












20 


100. 
94 706 
88.8888 
84.2222 
80 ( 000 
76.1905 
72.7272 
69. r 651 
66 . 6666 
64.0000 
61 5385 










21 










22 


100. 
S*4.2'25 

90.0000 
85.7143 
81.81K1 

78.2608 
75 0(100 
72.0000 
69 2308 








23 








24 








25 


100. 
95.4545 
91.3044 

87.5000 
84.0000 
80.3461 






26 






27 
28 


100. 

95.8333 

92.1000 
8S.46I5 




29 
30 


100.00 



*A represents the per cent of fat that is desired in cream. 
tLelt-hand column H represents the per cent of fat in cream on hand. 

If cream is to be standardized with whole milk the result found 
by the intersecting columns represents the pounds per hundred 
or the per cent of the quantity which is cream of the per cent of 
fat on hand. 

To illustrate: If cream containing 20 per cent of butter fat is 
desired and cream containing 26 per cent of butter fat is on hand 
then 72.7 per cent of the quantity desired must be cream contain- 
ing 26 per cent of butter fat and 27.3 per cent of the quantity 
must be 4 per cent milk. 

—3 



32 FUNDAMENTAL DAIRYING 

DIVISION 11. 

STANDARDIZATION OF CREAM. 

The principal difference between milk and cream is that in 
cream a larger portion of the water is displaced with butter fat 
and since the variations lie mainly between the butter fat and 
the water the same methods that apply to the standardization of 
milk will apply to the standardization of cream. 

83. Q. What apparatus is necessary for standardizing? 

A. The apparatus necessary for standardizing milk or cream 
is a creamer, or much better a cream separator, a Babcock tester, 
scales, and a mixing vat. 

DIVISION 12. 

Rules for Calculating Butter-Fat Equivalent in Differ- 
ent Products. 

84. Q. How can the price per gallon of cream equivalent to the price of 
butter fat be found ? 

A. Multiply the pounds of cream per gallon by the per cent of 
butter fat in the cream, the product will equal the pounds of fat 
per gallon of cream. Divide the number representing the price 
per gallon of cream by the number of pounds of butter fat, the 
quotient will equal the price per pound of butter fat. 

To illustrate: What is the price per pound of butter fat if 
cream containing 20 per cent fat sells for 50 cents per gallon? 

As stated before, a gallon of 20 per cent cream weighs 8.3 
pounds. 

8.3 X .20 = 1.66, the pounds of butter fat in one gallon which 
is worth 50 cents. 

$.50 -^-1.66 = $.30, the price of one pound of butter fat. 

85. Q. How can the price per gallon of cream at a certain price per 
pound of butter fat be found'? 

A. 'Multiply the pounds of cream per gallon by the per cent of 
fat in the cream, the product will be the number of pounds of but- 
ter fat in one gallon of cream. Multiply this product by the price 
per pound of butter fat you desire, the product will be the price 
per gallon for cream. 

To illustrate: At 32 cents per pound of fat what would be the 
price per gallon of cream containing 27 per cent butter fat? 

8.3 X .27 = 2.241 pounds of fat in 1 gallon. 

2.241 X 32 = 71.712, or 72 cents, the price of the 27 per cent 
cream. 

86. Q. How can the equivalent price per gallon for cream containing dif- 
ferent per cents of butter fat be found? 

A. This is best calculated on a basis of proportion. Divide the 
means by the extremes. 

To illustrate: If cream containing 20 per cent butter fat is 
worth 60 cents per gallon what is cream worth containing 25 per 
cent butter fat? 

.20 : .25 :: .60 : x 

60 X .25 = 15 



AND DAIRY ARITHMETIC. 33 

15 -=- .20 = 75, or 75 cents, the equivalent worth of 25 per cent 
cream in comparison to the worth of 20 per cent cream at 60 cents 
a gallon. 

DIVISION 13. 

DETECTION OP ADULTERATION IN MILK. 

87. Q. Can adulteration of milk with water be detected? 

A. Yes. This can be determined by means of the lactometer 
(Quevenne being the best), as it has a scale corresponding to the 
specific gravity of milk. The graduated scale from 15 to 40 being 
equivalent to a specific gravity of 1.0 L4 to 1.010; thus a milk which 
has a specific gravity of 1.032 would show on the lactometer as 
reading of 32. These lactometers are to give the specific gravity 
at a temperature of 60 : P., and as it is not always convenient to 
have the temperature of the milk at 60° when the reading is taken, 
corrections may be made for slight variations (not more than 10°) 
by adding to the lactometer reading .1 (to) for each degree of tem- 
perature above 60°, or substracting .1 for each degree below 60 D . 
For example, the lactometer reading is 29 and the temperature 
68, then the correct reading or specific gravity for 60° would be 
29 +.8 = 29.8. Had the temperature been 56°, the correct reading 
would be 29 —.4 = 28.6. 

The average composition of milk is as follows: 

Water, 87 to 88 per cent. 

Pat, 3.0 per cent and upwards. 

Solids not fat, 8.5 to 9.5 per cent. 

The specific gravity or lactometer reading of pure milk ranges 
from 28 to 34, skim-milk 33 to 36. 

The next step to be taken is to determine the per cent of fat, 
which is done by means of the Babcock tester. Then, having ob- 
tained the per cent of fat and the specific gravity, the per cent 
of solids not fat may be calculated by the following formula: 

T x P 

— -r — = per cent of solids not fat. 

L = Lactometer reading or specific gravity at 60°. 

P = Per cent of fat. 

To find the extent to which a known sample of milk has been 
watered, multiply the per cent of solids not fat in the adulterated 
sample by 100, and divide by the per cent solids not fat in pure 
sample. The result will be the number of pounds of pure milk in 
100 pounds of the sample examined, and the remainder will be the 
number of pounds of water. Pure milk contains not less than 8.5 
per cent solids not fat, and often as high as 9 and 9^ per cent, and 
where it is not possible to get a sample of the pure milk for test- 
ing, use 8.5 as a standard for the first half of the season and 
gradually increase to 9 as the season advances and as the period 
of lactation advances. To make the foregoing more plain, take 
the following example : 

Lactometer reading 28, temperature 54°, per cent fat 2.6, and 
suppose the pure milk to test 9 per cent solids not fat. Find the 
per cent of water added. 



34 FUNDAMENTAL DAIRYING 

The correct lactometer reading is 28 minus .6, or 27.4. Substi- 
tuting for formula we have : 

Of) Q 

27.4 + 2.6 = — — =7.5 per cent solids not fat; then 
4 

7.5 X 100 (Peroent > soUdS j DQt fat^ = _jj>Q = g 3 3 per cent pure milk . 

9 y 

then 100 — 83.3 = 16.6 per cent water in the adulterated sample. 

88. Q. What is the function of the lactometer? 

A. The lactometer displaces the milk, or in other, words com- 
pares the weight of milk with the weight of an equal volume of 
water. Milk becomes heavier as the per cent of solid not fat 
increases. Fat being lighter than water causes an error which 
must be taken into consideration. 

89. Q. What precautions are necessary in taking the lactometer reading? 

A. (1) It is necessary to mix the milk well before taking the 
lactometer reading. Do this in such a manner that it will not 
froth or foam. (2) If it is necessary to change the temperature 
of the milk, do so in such manner that the temperature will be 
uniform throughout. (3) Always let mhk stand an hour after 
being drawn from the cow before testing with the lactometer, as 
it is saturated with air and has not reached its maximum density. 

90. Q. What is indicated when the lactometer reading is too high and 
the per cent of fat too low? 

A. If the reading is 33 and upwards, and the per cent of fat 
is 3 or below, it indicates skimming. 

91. Q. What is indicated if the lactometer reading is too low and the 
per cent of fat is low? 

A. If the lactometer reading is 28 or below, and the fat is 
correspondingly low, it indicates watering. 

92. Q. What is indicated when the lactometer reading is normal, or 
slightly below normal and the per cent of fat very low? 

A. If the lactometer reading does not correspond with the per 
cent of fat as given above, it indicates that the milk is both 
skimmed and watered. 

EXAMPLE. 

27.4 is the corrected lactometer reading. 1.6 per cent is the 
per cent of butter fat in the above samples of milk. 27.4 is 85.6 
per cent of 32, which is the normal specific gravity of milk, or in 
other words the sample has been reduced 14.4. Hence, if this 
sample of milk had been adulterated with water only, the per cent 
of butter fat would be reduced proportionally; or, for example, 
85.6. per cent of 3 = 2.56 per cent, which should be the per cent 
of butter with the above per cent of dilution. However, from the 
above it will be noticed that the butter fat, 1.6 per cent, has been 
reduced 53.3 per cent, hence the difference between 85.5 and 53.3, 
or 32.3 per cent, of butter fat must have been skimmed off the 
milk, aside from being adulterated. 



AND DAIRY ARITHMETIC. 35 

DIVISION FOURTEEN. 

THE ACID TEST. 

93. Q. What causes milk to sour on standing for eighteen to twenty 
hours at a temperature of 60 to 70° F? 

A. This change is brought about by bacteria converting the 
milk sugar of the milk into lactic acid. It generally takes about 
18 to 20 hours at 65 to 70° for them to grow in sufficient number 
to turn the milk sour enough so that it clabbers. 

94. Q. Why does milk clabber? 

A. Clabbering of milk is due to the formation of lactic acid, 
which causes the casein of the milk to coagulate. 

95. Q. Has lactic acid any value in milk from a commercial standpoint? 
A. It is chiefly responsible for the flavor of butter and cheese, 

but great care must be taken in their manufacture that a proper 
amount of this acid be developed. 

96. Q. If too much acid is developed how would it affect the butter? 

A. Butter would not have such a good keeping quality and 
would not have the proper flavor. 

97. ,Q. If the acid exists in milk in solution with the other liquids, how 
can the amount be readily determined? 

A. By neutralizing the acid with alkalies. 

98. Q. What is meant by alkalies? 

A. An alkali is a substance that has its chemical properties di- 
rectly opposite to an acid. Either of these is a powerful agent for 
disintegrating and corroding much of the organic and inorganic 
matter, but when the two are united they lose this power. Alkalies 
are such substances as lime, lye, soda, etc. However, for testing 
purposes they must be chemically pure. Hence, if lime is added 
to sour milk, the acid unites with the lime, forming a substance 
which is neutral, neither alkaline nor acid. 

99. Q. Does a certain amount of alkali neutralize a certain amount of 
acid? 

A. Yes ; if the per cent of alkalinity of a solution is known, and 
the amount added to an acid substance, the per cent of acid in the 
solution can be calculated. 

100. Q. How can one tell when the alkali has neutralized the acid? 

A. By means of an indicator. This indicator is colorless in 
appearance if added to the acid, but turns pink when added to 
alkali, hence if a few drops of this indicator (which is commonly 
known as phenolphthalein) be added to the milk, the same will 
remain colorless until sufficient alkali has been added to neutralize 
the acid, and by adding a slight amount more the solution changes 
to a pink color. 

101. Q. What are the names of the tests on the market? 

A. There are four tests in use at the present time: One devised 
by Professor Mann, known as the Mann's test; the second by Pro- 
fessor Farrinerton, known as the Farrington Alkaline Tablet test; 
the third by Professor Van Norman, known as the Van Norman 
Alkali test, and the fourth, the Marschall Acid test. 



36 FUNDAMENTAL DAIRYING 

102. Q. How do you determine the acid by means of the Mann's test? 

A. The Mann's test consists of a 50 cubic centimeter burette, a 
50 cubic centimeter pipette, a white porcelain cup, and a glass 
stirring rod. This alkali can be bought in gallon bottles, and is 
made by dissolving four grams of sodium hydroxide, to which 
enough distilled water is adder! to make one liter of solution. This 
makes what is commonly known as a 10th normal solution. Eich 
cubic centimeter, containing .004 of a gram of sodium hydroxide, 
will neutralize .009 of a gram of lactic acid. This is obtained from 
the fact that a normal solution of lactic acid contains 90 grams of 
acid in each liter, or 1,000 cubic centimeters. A 10th normal solu- 
tion would then contain one-tenth as much, or 9 grams to each 
liter, and a cubic centimeter, which contains .001 as much as a 
liter, would contain .009 of a gram of lactic acid. With the ap- 
paratus and solution on hand, measure 50 cubic centimeters of 
cream with a pipette into a beaker, then with the same pipette 
add 500 cubic centimeters of water. Then add five drops or more 
of indicator. Fill the burette to the zero mark with netralizer, but 
before doing this be sure and see that the burette is absolutely 
free from water and acids. Probably the best way is to rinse the 
burette with a little of this solution. Now add the solution to the 
cream in a very slow manner until you notice that the solution ap- 
pears very reluctant in destroying the pinkish color on stirring. 
Then this neutralizing solution should be added drop by drop only. 
The moment the cream remains pink, the acid has been neutral- 
ized. The number of cubic centimeters of alkali added to the 
cream is read on the burette, and from this the percentage of 
acid is calculated in the following manner: The number of cubic 
centimeters of alkali multiplied by .009, divided by the number of 
cubic centimeters of cream, and multiplied by 100. 

Example. — It required 32 cubic centimeters of alkali to neutral- 
ize £0 cubic centimeters of cream; what per cent of acid is in the 
cream? 

The formula would be like this: 

32 x .009 ... _- 

— x 100 = .0/6. 

50 

103. Q. How do you determine the acid by means of the Farrington Al- 
kaline Tablet test? 

A. The Parrington alkaline tablet test works on the same prin- 
ciple as the Mann's test. Instead of the neutralizer being in a so- 
lution form, as in the Mann's test, it is put up in tablets, each 
tablet containing 3.8 cubic centimeters of a 10th normal solution, 
and if the solution is made by dissolving 10 tablets in 100 cubic 
centimeters of water, each cubic centimeter of the solution will 
be equal to .38 of a tenth normal alkali, and will therefore neu- 
tralize .38 of .009 grams, or .0034 grams of lactic acid. There- 
fore by multiplying the number of cubic centimeters of tablet so- 
lution used by .009, and dividing by the same number of grams of 
milk taken, will give the per cent of acidity. The grams of milk 
must be calculated according to the specific gravity. Example: 
20 cubic centimeters of cream require 3b cubic centimeters of tab- 
let solution to neutralize the acid. 



AND DAIRY ARITHMETIC. 37 

104. Q. What will be the per cent of acid in the milk? 

A. It will be .0034 times 36, divided by 20 times 1.032, times 
100, or the specific gravity of milk. 

■ O034xa6 -Xl00 = .59+ 

20 X 1.032 

A simpler method is to dissolve five tablets in enough water to 
make 97 cubic centimeters solution. The tablets must be dis- 
solved so that it becomes a perfect solution. Measure out with 
a Babcock pipette 17.6 cubic centimeters of the milk or cream to 
be tested into a white porcelain cup (a white cup is preferable 
because one can more easily see the pink color). Add solution to 
milk or cream until a permanent pink color is obtained, the same 
as in the Mann's test. Read the number of cubic centimeters 
solution used to change the color, and this will indicate the num- 
ber of hundredths ol one per cent of acidity in milk or cream. 

Example. — If it requires 50 cubic centimeters of tablet solution 
to neutralize the acid of the cream, then the acidity wquld be .5 
per cent. 

105. Q. How can you obtain the per cent of acidity by means of the Van 
Norman test? 

A. The operation again is the same as in the preceding tests, 
except in this particular test a normal solution of caustic soda is 
used. The apparatus required is a 17.6 cubic centimeter Bab- 
cock pipette, a 100 cubic centimeter cylinder, and a two quart 
bottle, graduated at 1850 cubic centimeters, and 37 cubic centi- 
meters of normal solution of caustic soda. A few drops of indi- 
cator must be used the same as in the Mann's acid test. The 
caustic soda solution must be prescribed by a reputable chemist, 
one who can be depended on to furnish it of standard strength 
and accurately measured. A two-quart bottle, with a long slo- 
ping neck such as is used for mineral water, may be graduated 
by measuring into it carefully with a 100 cubic centimeter cyl- 
inder, 1850 cubic centimeters of water, and then with a fine file 
marking the point on the neck to which the water rises. To pre- 
pare the solution, pour into this large graduated bottle 37 cubic 
centimeters -of normal caustic soda solution, rinse the little bottle, 
empty this, rinse water into the large bottle, then fill with water 
condensed from the steam pipe, if it is free from boiler com- 
pounds and oil; if not use rain water, and fill the large bottle to 
the mark on the neck. This makes a 50th normal solution ready 
for use. With a Babcock pipette measure out in a white cup, or 
in a common composite sample jar 17.6 cubic centimeters of 
cream or milk to be tested which has been well stirred, rinse the 
pipette out with clean water, put the rinse water into the cream 
sample, and add four or five drops of phenolphthalein indicator. 
Having filled the cylinder to the top or 100 cubic centimeter mark 
with what is known as 50th normal alkali solution, pour slowly 
into the cream sample, mixing with a rotary motion of the hand, 
or stirring with a glass rod until there is a pink color noticeable, 
which does not disappear immediately by continued stirring. Note 



38 FUNDAMENTAL DAIRYING 

the number of cubic centimeters of alkali solution required to bring 
about this result. This will indicate the number of hundredths per 
cent of acid, since one cubic centimeter of the alkali will neutralize 
.01 per cent of acid when 17.6 cubic centimeters of milk or cream 
are used. 

106. Q. How can you obtain the per cent of acidity by means of the Mar- 
schall test? 

A. In this acid test the neutralizer used is the regular standard 
Jq normal alkali, which can be obtained from all dairy supply 
houses and experiment stations. 

The A. Marschall acid test contains the following parts: 
Combined burette and bottle for the neutralizer. 
9 cubic centimeter pipette. 
Bottle of indicator. 
A- gallon bottle of neutralizer. 

It is necessary only to fill the burette bottle with neutralizer, 
place it on a small box or shelf at a convenient height, and the 
acid test is ready for use. 

After carefully mixing the milk or cream, fill the 9 cubic centi- 
meter pipette, empty it in the cup and add a couple of drops of 
the indicator. If heavy cream is tested, it is preferable to fill the 
pipette again with water, and add the rinsing water to the con- 
tents of the cup. Fill the graduated burette by tipping the bottle 
and place level again. Adjust the burette and rubber stopper so 
that the neutralizer will stand at the zero mark in the burette, 
then let the neutralizer run into the cup a little at a time, shaking 
the cup by circular motion, until the contents has attained a pink 
shade and does not turn white again within five to ten seconds. 
The number of cubic centimeters of the neutralizer used will then 
directly show how much acid the milk or cream contained, giving 
it 'in 0.1 per cent acid. If 2 cubic centimeters of neutralizer has 
been used, the milk contained two tenths of one per cent, and if, 
for instance, a sample of cream takes 5.6 cubic centimeters of 
neutralizer, it contained 56 hundredths of 1 per cent of acid, gen- 
erally written as .2 per cent acid and .56 per cent acid. To facil- 
itate the readings, the burette is graduated in to of one cubic 
centimeter only, but ia cubic centimeter can easily be read off 
when required. As all tests start at the zero mark, there are no 
calculations necessary to determine how much neutralizer has 
been used, with the resulting possible errors. 

Before starting the test, lift the rubber stopper in the neck on 
top of the bottle and replace securely. This operation releases 
the pressure in the bottle, and should be repeated each time the 
neutralizer does not run freely from the burette. The burette 
valve is a ball valve, and is worked by pressing the rubber tubing 
between the fingers. 

107. Q. Does a change in the per cent of acidity change the flavor? 

A. Yes; the greater the amount of acid developed in cream the 
more sour it will taste. 

108. Q. What amount of acid should there be in milk when it is no 
longer known as sweet milk? 



AND DAIRY ARITHMETIC. . 39 

A. Milk received at the factory should not contain more than 
.2 per cent acid, and milk containing- .25 per cent acid and over 
can not be pasteurized. Most butter makers would refuse milk 
showing more than .2 per cent acid. 

109. Q. What per cent of acid should there be in cream for butter 
making? 

A. Cream ready to churn should contain .5 to .65 per cent acid, 
according to whether mild or highly flavored butter is wanted, 
and also depending upon the per cent of fat in the cream. The 
higher the per cent of fat the less acid is needed. 

110. Q. What per cent of acid should there be in starters used for butter 
and cheese making? 

A. Starter for butter or cheese should be used immediately, or 
else cooled down quickly, when it shows .7 to .85 per cent acid. 

111. Q. Is there a more convenient way to test a great number of 
samples of milk? 

A. If many samples of milk are tested at the receiving plat- 
form with the Marschall test, it is convenient to get a couple 
dozen 2-oz. bottles, with wide mouths, and in each fill 2 cubic cen- 
timeters of neutralize!' from the burette, and also a couple of 
drops of indicator. The 9 cubic centimeters of the milk taken as 
sample is then simply added to one of the bottles and shaken. If 
the mixture does not turn white the milk contains less than .2 per 
cent acid. This is generally taken as a standard. 

Dairy Bookkeeping. 

112. Q. What is meant by dairy bookkeeping? 

A. It is keeping a record of all transactions conducted in the 
dairy business. 

113. Q. What is the object of bookkeeping? 

A. The object of bookkeeping is to show in detail the money 
spent for certain articles, the income from certain articles, and 
the profits or loss of the business. 

114. Q. How do you proceed to keep books? 

A. The first step is the recording cf every business transaction. 
The records of milk and cream are usually kept on milk and cream 
sheets. All other accounts are generally recorded in a day book. 
The second step is to transfer these entries into a journal or 
ledger. There are two systems of bookkeeping. One is known 
as the single entry system, and the other is known as the double 
entry system. In the single entry system accounts are kept with 
persons only, while in the double entry accounts are kept with 
persons and articles. 

115. Q. Which is the more practical system for dairy bookkeeping? 

A. The single entry system, for the reason that we have few 
articles to deal with in creamery work. 

116. Q. Can the single entry system be used where whole milk is pur- 
chased on the butter-fat basis as well as where the cream is purchased on the 
same basis? 



40 



FUNDAMENTAL DAIRYING 



A. Yes; ordinarily where milk is purchased it is the custom to 
pay once a month, but where cream is purchased it is paid for 
every day. The daily check system, in which the cash is paid to 
the party that brings in the cream the day after the cream is de- 
livered, is probably the most satisfactory. The following is an il- 
lustration where whole milk is purchased. 

The following persons, A, B, C, and D delivered milk to a 
creamer: 

A delivers 2,100 pounds of milk in the month of December. 

B delivers 1,500 pounds of milk in the month of December. 

C delivers 2,700 pounds of milk in the month of December. 

D delivers 600 pounds of milk in the month of December. 

A composite testis taken daily and tested every fifteen days. 
A delivers 1,300 pounds of milk the first fifteen days, which tested 
4 per cent, or 1,300 times .04 = 52, No. pounds of butter fat. He 
delivers 800 pounds the last part of the month, tested 4.4, or 35.2 
pounds of butter fat. 

B delivered the first half of the month 800 pounds, which tests 3.4 
and contains 27.2 pounds of butter fat. The last half he delivers 
700 pounds, which contains 3.6 per cent of butter fat, or 25 pounds. 

C delivers 1,800 pounds of milk the first half, which contains 3.5 
per cent of butter fat, or 63 pounds, and 900 pounds the last half, 
which tests 3.8 per cent, or 34.2 pounds of butter fat. 

D delivers 300 pounds the first half of the month, testing 4.7, or 
14.1 pounds of butter fat, and the second half 300 pounds, testing 
4.9, or 14.7 pounds of butter fat. 

The following summary shows the total amount delivered by 
each and the grand total: 

A 87.2 

B r>2.2 

C 97.2 

D 28 8 

Total 202.6 

SALES OF BUTTER FOR DECEMRER. 



Date. 


Pounds. 


Price 
per lb. 


Total. 




50 
60 
105 
100 


$0 24 
25 
23 
22 


$12 00 


1(5 

28 


15 00 
24 15 




22 03 


Totals 


315 




$7.3 15 









From the above statement of butter sales it will be seen that 
315 pounds of butter were made from the 262.2 pounds of fat, 
which sold for $73.15. The charge for making a pound of butter 
was 3 cents. For 315 pounds it would be $9 45, which, deducted 
from the butter value $73.15, leaves $63.60 to be distributed among 
A, B, C, and D. Since the patrons receive their money according 
to the pounds of butter fat delivered, it would be necessary to re- 
duce this to a butter-fat basis. Hence, $63.60 divided by 262.6 
would be 24.3 cents, the value of a pound of butter fat. 



AND DAIRY ARITHMETIC. 41 

According to the above, A would receive for his share 84 times 
24.3, or $20.41. 

B would receive 54.2 times 24.3, or $13.17. 

C would receive 97.4 times 24 3, or $23.66. 

D would receive 28.8 times 24.3, or $6.99. 

Whenever the plant is run independently or for a stock com- 
pany, and where a certain price for butter fat is guaranteed, all 
such items as labor, coal, ice, oil, butter color, salt and packing 
and investments on capital must be itemized separately. 

117. Q. How do you calculate where milk and cream are both taken at 
the same factory? 

A. Ordinarily a half cent more per pound is paid for butter fat 
in cream than for butter fat in whole milk. 

118. Q. How can you calculate what price is to be paid to the producer 
by the cash system, where the butter fat is paid for immediately after its de- 
livery to the factory'? 

A. This fat is generally paid for in such cases according to the 
New York market or some private market. Due allowance iust 
be made for any decline in price before the butter reaches the 
market. 

119. Q. Flow is butter graded on the market? 

A. By the terms "extras, "first grade, second grade, and third 
grade. 

120. Q. What are the rules governing' these grades of butter? 

A. Extras. — Shall consist of the highest grade of butter pro- 
duced during the season when made, scoring 93 points or higher. 

Flavor. — Must be quick, fine, fresh and clean if of fresh make, 
and good, sweet and clean if held. 

Body. — Must be firm and solid, with a perfect grain or texture, 
free from salviness. 

Color. — Must be uniform, neither too light nor too high. 

Salt. — Well dissolved, thoroughly worked in, not too high nor 
too light salted. 

Package. — Good and sound as required in classification. 

Firsts. — Shall be a grade just below Extras, scoring 87 points 
or higher, lacking somewhat in flavor, which, however, must be 
good, sweet, and clean. All other requirements same as in Extras. 

Package. — Good and uniform. 

Seconds. — Shall consist of a grade just below Firsts, scoring 
80 points or higher. 

Flavor — Must be fairly good and sweet. 

Body. — Must be sound and smooth boring. 

Color. — Fairly good, although it may be somewhat irregular. 

Salt. — May be irregular, high or light salted. 

Package. — Same as required in Firsts. 

Thirds. — Shall consist of butter below Seconds, scoring 75 
points or higher. 



42 FUNDAMENTAL DAIRYING 

Flavor. — Reasonably good, may show strong tops and sides. 
Body. — Not smooth boring. 
Color. — Mixed or streaked. 
Salt. — Irregular. 
Package. — Miscellaneous. 

121. Q. Do you calculate the dividends in the cheese factory the same as 
in the creamery? 

A. In this case the milk is paid for according to the fat it con- 
tains, the same as in creameries. But ordinarily the cost of mak- 
ing cheese is figured on a basis of \\ cents per pound of green 
cheese. This is deducted from the total amount of money re- 
ceived from cheese and divided among the patrons according to 
the pounds of butter fat they deliver, the same as in the creamery. 

122. Q. Approximately how much cheese can be made from a hundred 
pounds of milk? 

A. This is ordinarily found by multiplying the per cent of fat 
in milk by 2.7.* 

For example, 100 pounds contains 3 per cent of butter fat. The 
same, under average conditions, would make 8.1 pounds of cheese. 
This is, however, estimated on an average milk basis. 

123. Q. Is there a more accurate method of determining' the pounds, of 
green cheese made from milk? 

A. Yes. If the percentages of solids not fat (s) and the per cent 
of fat (f) is known, the same can be calculated with the following 
formula: 

Yield of green cheese = 1.58 (^ + .91 f ) 

Assuming that 4,000 pounds of milk, containing 3.5 per cent of 
butter fat, were delivered to a cheese factory. This milk also 
contains 9 per cent of solids not fat. Prom the above formula for 
every 100 pounds of milk we substitute the following values: 
158(| +.91 X 35). This equals 9.67, which is the number of 
pounds of cheese that can be made from 100 pounds of milk, since 
from the 4,000 pounds of milk the yield of green cheese would be 
40 times 9.67, or 386.8. the number of pounds of cheese. 



DIVISION FIFTEEN. 

Dairy flanagement. 

124. Q. Does the per cent of butter fat and other constituents' in cow's 
milk vary? 

A. Yes. They vary for several reasons. (1) They vary in the 
average milk given by different breeds of cows. (2) They vary in 
milk of individual animals. 

The following are the causes which influence this individual 
cow: (1) Composition of feed. (2) Change of feed. (3) Treat- 
ment of the cow. (4) Health of the cow. (5) If the cow is unusu- 
ally excited. (6) If the milkers are changed, or manner of milk- 



— *ACJording to Van Slyke. 



AND DAIRY ARITHMETIC. 43 

ing. (7) Length of time between milking. (8) Length of time 
since calving. 

125. Q. Does a cow manufacture milk from food? 

A. Yes. A cow is a machine, so far as the manufacture of milk 
is concerned. She takes crude feeds, such as hav, cornstover, 
silage, grass, corn, bran, gluten-meal, etc., and converts them 
into a refined product which is milk. 

126. Q. What is a food? 

A. A food is anything capable of digestion by the animal that 
will sustain or help to sustain life. 

127. Q. What is a nutrient? 

A. One of the constituents of fodders or feeds, or any sub- 
stance which nourishes by sustaining life and repairing body 
waste. 

128. Q. What are the chief nutrients necessary in a food? 
A. Water, ash, protein, carbohydrates, and fats. 

129. Q. What is protein? 

A. The name of protein, like that of casein in milk, is applied 
to a series of complex compounds containing nitrogen, carbon, 
oxygen, hydrogen, sulphur and sometimes phosphorus. Prac- 
tically all the nitrogen of fodder is in the protein. Blood and 
muscle are rich in nitrogen. The white of an egg is rich in 
nitrogen. 

130. Q. Of what special use is protein to the animal? 

A. It furnishes the material out of which both the cell walls 
and the life-giving fluids (protoplasm) are made. It is absolutely 
essential to the blood, muscles, bones, nerves, hair, and hoof, be- 
cause no other nutrient of foods possesses this property. Pro- 
tein can, also, perform the same function as the carbohydrates 
and fat. 

131. Q. What are carbohydrates and their special use to the animal? 

A. Carbohydrates contain carbon, oxygen, hydrogen, but no 
nitrogen. They are such material as starches, sugars, and gums. 
They produce heat in the body, practically in the same way as the 
ordinary combustion in the air. They may also be changed into 
fats and stored in the body. For illustration: In fattening swine 
a large quantity of corn is fed which contains mostly starch. 

132. Q. What difference is there between fats and carbohydrates? 

A. Pats perform the same function in the body as carbohy- 
drates, except that they are worth two and a quarter times more 
than carbohydrates. 

133. Q. What is ash? 

A. Ash in a feed is a mineral constituent the same as the ash in 
milk and performs the same function of supplying food for the 
various tissues. The larger quantity but not all of the ash of the 
body is to be found in the bones. *rz 



44 FUNDAMENTAL DAIRYING 

134. Q. Is it desirable to have the quantity of each of these nutrients 
furnished according to the work the animal does'? 

A. Yes. A cow weighing 1000 pounds and giving 35 pounds of 
milk should have approximately 2£ pounds of protein per day, 12| 
to 13 pounds of carbohydrates, .8 of a pound of fat, and .7 of a 
pound of ash. This depends somewhat on the individual cow. 

135. Q. Will corn and corn-stalks produce a maximum amount of milk 
if fed alone to a cow? 

A. Corn alone is found not to induce a cow to give a large quan- 
tity of milk, because the nutrients are not in the right proportion. 
Corn is composed principally of starches and fats; hence, an in- 
sufficient quantity of protein is supplied to produce milk and at 
the same time properly nourish the body. If enough corn is fed 
to supply the proper amount of protein, the digestive organs will 
be overtaxed with carbohydrates. This is wasteful feeding. 

136. Q. What crops and grains are rich in protein, and which will help 
to correct the deficiency of this particular nutrient when corn Is fed? 

A. Clover, alfalfa, peas, vetches, gluten-meal, linseed meal, and 
cottonseed- meal, etc. 

137. Q. What is roughage? 

A. Those food materials which contain a considerable amount 
of bulk in proportion to their digestible nutrients, such as straw, 
hay, corn stover, etc., are called coarse fodders or roughage. 

138. Q. What are concentrates? 

A. Concentrates are those foods which have little bulk in pro- 
portion to the nutrients they contain, such as gluten meal, corn- 
meal, cottonseed-meal, etc. 

139. Q. What is a nutritive ratio? 

A. A nutritive ratio is a ratio between the digestible protein on 
the one hand and the digestible carbohydrates plus 2.4 times the 
digestible fat on the other hand. 

140. Q. What is the nutritive ratio of corn? 

A. On the average, 1 of digestible protein to 9.7 of digestible 
carbohydrates and fat. 

141. Q. What should the proper ratio be for the proper milk produc- 
tion? 

A. About 1:65 or 1:7. 

142. Q. How many pounds of the nutrients are necessary to manufacture 
a pound of milk with the average cow? 

A. About: .021 pounds of protein plus food of maintenance 
.07 per cwt. live weight. 
.220 pounds of carbohydrates plus food of mainte- 
nance .7 per cwt. live weight. 
.018 pounds of fat plus food of maintenance .01 per 
cwt. live weight.* 

143. Q. Are more nutrients required if a cow produces more milk? 



♦According to Prof. T. L. Heacker. 



AND DAIRY ARITHMETIC. 



45 



A. Yes. The nutrients required in rniJk production depend, 
first, on weight of cow, greater weight requiring more nutrients; 
second, on milk yield, the greater the yield, the more nutrients 
required; third, on quality of milk, the richer the milk, the more 
nutrients necessary; fourth, on age of cow. 

144. Q. Is there such a thing as an all-round food that contains the nu- 
trients in the proper proportion for the production of milk? 

A. Yes. Pasture grass, because it is nature's food, supplying 
each of the necessary food constituents in nearly the proper pro- 
portion. 

145. Q. May hay or grain contain the nutrients in the proportion re- 
quired by animals? 

A. Very seldom. Perhaps clover or alfalfa hay or oats come 
nearest to it. 

146. Q. How can you make a ration that contains all the nutrients in 
proper proportion? 

A. By looking up the composition of each feed that is conven- 
ient and cheap to obtain in a certain locality, and compiling them 
in such quantities that the total should contain 23 to 26 pounds of 
dry matter to every 2 pounds of digestible protein and 14 pounds 
digestible carbohydrates and fat. Foods selected in this way and 
put in rations are known as balanced rations. 

147. Q. Give an example of a balanced ration. 

A. 



Pood. 


Lbs. 


Digestible 
Protein. 


Digrestible 

Carbohydrates. 


Digrestible 
Fat. 




10 

30 

4 

6 


.35 
.27 

1.40 


4.98 
3.39 
2.62 
3.04 


.14 




.21 




.06 




.16 




50 


2.37 


14.03 


.57 



148. Q. What is a maintenance ration? 

A. It is a ration furnishing sufficient nutrients to maintain the 
animal, without gain or loss in body weight, but not enough to 
furnish material for the production of milk. 

149. Q. What is a productive ration? 

A. It is one furnishing nutrients in excess of maintenance re- 
quirements. 

150. Q. Do all cows pay for their keep? 

A. No. This can be easily discovered by adding the cost of 
feed consumed by the cow and comparing it with the money value 
of her products. 

151. Q. How does the treatment of the cow govern the per cent of solids? 

A. The more the cow is abused by being chased or beaten or 
kept in cold stables or out in severe storms, the more severe it is 
on her system and the more feed or nutrients are required to re- 
pair the resultant losses. 



46 FUNDAMENTAL DAIRYING 

152. Q. Will heavy grain feeding improve the quality of the milk? 
A. No, unless the cow is starved or underfed. 

153. Q. Do cows grazing in luxuriant pastures produce milk which is 
richer in quality of solids? 

A. The increase in the amount of butter fat, which is often 
noticed and is the result principally of the change of feed, doubt- 
less comes from the fact that more, but not richer, milk is pro- 
duced. This rise of solids in milk during spring pasturing lasts 
only a short time with cows that have been properly fed. 

154. Q. Is the capacity of a cow to produce butter fat or milk limited? 
A. Yes. Each individual cow has her capacity to produce milk 

and butter fat. 

155. Q. How can the herd be improved or made to yield more and better 
milk? 

A. By selling the poor cows and by selecting calves from good 
cows, and bulls, to replace the poor cows. 

156. Q. How can the butter-fat value of a cow be determined? 

A, By weighing the milk of a cow for two days each week, and 
during this time taking a composite sample of the milk. 

Example, — A cow gives 14£ pounds of milk the first morning's 
milking and 13i pounds the second morning's milking; 16 pounds 
the first evening's milking and 15 pounds the second evening's 
milking; or 59 pounds, which is the total for two days, or 29^ 
pounds, the average for one day of that week. An aliquot sam- 
ple of the milk must always be taken from the above milking. If 
the sample tests 4.1 per cent butter fat, it would indicate that 4.1 
per cent is the average of the above milk, or 4.1 X 29.5 = 1.2, the 
pounds of butter fat yielded per day. 

This scheme requires much less work than to test and weigh 
the milk every day and does not contain an error of more than 5 
per cent. 

157. Q. What amount of butter fat should a cow produce to pay for the 
feed she consumes for the year? 

A. This depends upon the amount of food she consumes, on the 
price of feed, and on the price of butter fat. According to a 
recent census, it requires about 215 pounds of butter fat to pay 
for the keeping and food of a cow for one year, with the average 
prices that existed for feed and products the past ten years. 

158. Q. How much butter fat should a cow produce in one year? 

A. A good cow should produce 240 or more pounds. Some 
cows have produced 700 pounds. 

159. Q. How can you calculate the cost of the food of a cow for one year? 

A. By finding the weight and the value of each food fed in the 
ration. The food fed to each cow need not be weighed daily, but 
by means of a measure the proper amount can be estimated. 



AND DAIRY ARITHMETIC. 47 

EXAMPLE. 

A cow is fed a ration of : 

Ensilage, 30 pounds at $1.50 per ton £0.0225 

Alfalfa hav, 15 pounds at $1.00 per ton 03 

Bran, 3 pounds at $18.00 per ton 027 

Corn-meal, 5 pounds at $12.50 per ton -03125 

Total cost $0.11 

If a cow was fed the above ration or a similar one, it would cost 
11 cents per day. The total amount of the ration should vary- 
somewhat according to the period of lactation. A cow eats more 
at the beginning of the period of lactation than is provided for in 
this ration, consequently more ought to be fed, but in the same 
proportion. However, she needs to consume decidedly less to- 
ward the end of the lactation period, so an average ration is here 
given that a good cow ought to consume. It is estimated that 
cows can be pastured in Kansas for five months at a cost of 
approximately 65 cents to 75 cents per month. However, from 
the experience of the average dairyman it is thoroughly proven 
that a cow cannot do well on dry pasture, such as is frequently 
the case, without the addition of some feed, so in order to give a 
cow feed sufficient to supply her needs either the area of the 
pasture must be increased or an additional quantity of feed 
added, which has been averaged as a total of $1.00 per month for 
five months, or $5.00. 

If a cow is pastured five months there remains 215 days, in- 
cluding the dry period, during which this ration of an average 
cost of 11 cents a day must be fed. 

215 days at 11 cents = $23.65 + $1.00 per month for pasture, 
or $5 00 = $28.65 which is the total cost of feed. 

Other expenses for keeping cow for one year are as follows : 

Feed cost $28 65 

Labor for one man to attend cow 12.50 

Cow worth $50.00 at 6 per cent interest on investment 3.00 

Deterioration by age, if bought at 5 years, average period of un- 
profitableness at 13 years • 2.50 

Death of cow by disease or accident, death of calves, average 

shrinkage 2.00 

Failure to breed, including maintenance of dry cows 2.50 

Cow barn for 20 cows costing $(500, well, tank, wind-mill and piping 

at $300, at 6 per cent interest on investment 2.75 

General maintenance expense, which includes taxes, fire and storm 
insurance, ordinary repairs, such as pasture fences, water fix- 
tures, paint, roof, etc 2.50 

Hauling 1200 pounds of cream at 10 cents per cwt 1-20 

Total expenditure for one cow for one year $57.60 

The income for an average cow, such as is estimated from the 
records of the scrub cows tested at the Kansas State Experiment 
Station, is as follows : 

6000 pounds of milk which -contains on an average 4.2 per cent 
of butter fat. 

6000 x .042 = 252 pounds of butter fat, which will make with 
an increase of ^. 

£ of 252 = 42. 



48 FUNDAMENTAL DAIRYING 

42 + 252 = 294 pounds of butter. 

294 pounds of butter sold at 22 cents = $64.62. 

If 20 per cent cream is made from these 6000 pounds of milk 

.. . , . 6000 X .042 252 

there would be - — = = 1210 pounds of cream. 

.20 .20 

1210 pounds of cream, or 145 gallons, sold at 50 cents per gal- 
lon =$72.50. 

6000 — 1210 = 4790 lbs. of skim-milk at 20 cents per cwt.=$9.58. 

1210 pounds of cream — 294 pounds of butter = 916 pounds of 
buttermilk, at 10 cents per cwt. = $0,916. 

The average value of the manure of a cow compared with the 
constituents in fertilizers is $29.50 per year. If we assume that 
through the waste and other causes, on the average farm, the 
manure has only one-third this value, the approximate value of 
the manure of a cow would be worth about $10.00. 

The calf is another source of profit. At birth a calf is gener- 
ally worth from $2.00 to $3.00, depending somewhat on the breed 
of the individual cow or sire. 

SUMMARY SHOWING PROFIT OF COW FOR ONE YEAR FROM BUTTER. 

Value of butter $64.62 

Value of skim-milk 9.58 

Value of butter-milk .92 

Value of manure 10.00 

Value of calf 2.00 

Total value of product $87.12 

Total cost of cow for one year 57. 60 

Total profit $29.52 

SUMMARY SHOWING PROFIT OF COW FOR ONE YEAR FROM CREAM. 

Value of cream $72.50 

Value of skim-milk 9.58 

Value of manure 10.00 

Value of calf 2.00 

Total value of product $94.08 

Total cost of cow for one year 57.60 

Total profit for one year $36.48 



STANDARD DAIRY PRODUCTS. 

The United States Department of Agriculture has established 
standards of purity for different dairy-food products by which all 
dairy products can be graded. The standards of these dairy pro- 
ducts are as follows: 

Milk (whole milk) is the lacteal secretion obtained by the com- 
plete milking of one or more healthy cows, properly fed and kept, 
excluding that obtained within fifteen days before and five days 
after calving. 

Standard milk is milk containing not less than three and one 
quarter (3.25) per cent of milk fat and eight and one-quarter (8.25) 
per cent of solids not fat, and which has an acidity equivalent to 
not more than two tenths (0.2) per cent of lactic acid. 



AND DAIRY ARITHMETIC. 49 

Blended milk is milk modified in its composition so as to have 
a definite and stated percentage of one or more of its constituents. 

Skim-milk is milk from which a part or all of the cream has 
been removed. 

Buttermilk is the product that remains when butter is removed 
from milk or cream in the process of churning. 

Pasteurized milk is milk that has been heated sufficiently to 
kill most of the active organisms present and to retard the devel- 
opment of their spores without changing the taste or flavor of the 
milk. 

Sterilized milk is milk that has been heated to the temperature 
of boiling water or higher for a length of time sufficient to kill all 
organisms present. 

Condensed milk is milk from which a considerable portion of 
water has been evaporated with or without the addition of sugar 
(sucrose). 

Standard condensed milk is condensed milk containing at least 
thirty-six (36) per cent of milk solids, of which not less than one- 
fourth is milk fat and not more than fifty (50) per cent of the total 
solids is added sugar (sucrose). 

Cream is that portion of milk, rich in butter fat, which rises to 
the surface of milk on standing, or is separated from it by cen- 
trifugal force. 

Standard cream is cream containing not less than eighteen (18) 
per cent of milk fat. 

Butter is the product of gathering in any manner the fat of 
fresh or ripened milk or cream into a mass, which also contains a 
small portion of the other milk constituents, with or without salt. 

Standard butter is butter containing not less than eighty-two 
and five tenths (82.5) per cent of butter fat. 

Renovated or process butter is the product obtained by melt- 
ing butter and reworking, without the addition or use of chemi- 
cals or any substances except milk, cream, or salt. 

Standard renovated or process butter is renovated or process 
butter containing not more than sixteen (16) per cent of water 
and at least eighty- two and five-tenths (82.5) per cent of butter 
fat. 

Cheese is the solid product obtained by coagulating the casein 
of milk by means of rennet or acids with or without the addition of 
ripening ferments and seasoning. 

Whole milk or full-cream cheese is cheese made from milk 
from which no portion of the fat has been removed. 

Cream cheese is cheese made from whole milk to which cream 
has been added. 

Standard whole-milk cheese, full-cream cheese, or cream cheese 
is cheese containing, in the water-free substance, not less than 
forty- eight (48) per cent of butter fat. 

Ice-cream is a product made from cream or milk and cream, 
with or without eggs, fruits, nuts, and harmless flavoring and 
coloring matters, sweetened with sugar (sucrose) and frozen into 
a mass of fine, granular texture. 



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